Can apartment management terminate leases over a rule tenants never signed?

Question

To live in the apartment building I reside in, a resident has to sign a Lease, and a document of Community Rules which are an "addendum" to that lease. Violation of the Community Rules counts as a violation of the Lease and thus a resident can be evicted for breaking them. The Lease states that it can only be terminated by (a) 30 days notice after the Initial Term of one year has expired, or (b) by a violation of the terms of the Lease (or Community Rules). The Community Rules "may be modified by the Board of Directors at any time". If the Board of Directors modify the community rules, I understand that residents have effectively already signed to agree to it.

The Lease and Community Rules never address the usage of The Front Door. The Front Door is locked outside of business hours, and requires a key to open from the outside, or can be opened by a button by anyone already inside the building. Each adult resident has a front door key. The Front Door, once opened, swings open slowly and remains open for around ten seconds before swinging slowly shut again.

The Former Building Manager requested residents not to open the door for "anyone who is not a resident", and never threatened leases over it. He was fired (for protesting a huge rent hike) and the New Building Manager has posted a sign on the door saying:

"do not open the door for ANY PERSON. Anyone caught on camera violating this rule can and will have Lease Termination Proceedings begin immediately".

There are two issues I see:

• Firstly, this rule is unreasonable, as "ANY PERSON" includes spouses, children, and "guests" (described and allowed in the Community Rules). It could also include any illegitimate person who loiters around The Front Door - if a resident opens the door for themselves, it will stay open for long enough for an illegitimate person to enter after the resident without the resident's consent or even knowledge.
• Secondly, I think this rule threatening Leases can not be legally enforced. Looking over our Lease, the only way a resident can be evicted is if they violate The Community Rules as written now or as modified by the Board of Directors. The new door rule threatening Leases is written only by the Building Manager, not the Board of Directors.

My questions are:

1. Am I right in thinking this is non-enforceable as it is neither Lease, nor Community Rules, and it is (apparently*) not a Board of Directors modification to the Community Rules?
2. Or is there any federal, state, or city rule which would allow management to terminate leases even without a violation of the Lease/Community Rules? (location is Greeley, Colorado, USA)
3. If I or another resident are told we are being evicted due to this rule, to where can we appeal? (Other than the Board of Directors). A good answer will also note what processes involve lawyers and/or are expensive.
4. Is threatening Leases over a rule that is non-enforceable actually illegal? As in, has the manager potential committed a criminal offense?

I realise management may terminate a lease with 30 days notice after the initial term has expired, so my question is only addressing threatened Leases still within their initial term (my own Lease is within its initial term until some time in 2019).

*Unless there is a loophole where the Building Manager represents the Board of Directors. If there is, I haven't seen evidence of it yet.

Addendums

• We know nothing about the Board of Directors other than that their name and logo is on the front of the Community Rules. Otherwise, there is no reference to them in our other paperwork.

• Some of the apartment units, such as my own, are federally subsidised (20-50% of rent depending on income), but not all the apartments in the building are.

Answer 1

Colorado has a pamphlet setting out the requirements and rights of landlords and tenants. As is standard, eviction requires a court process, and cannot be waived. The terms of the lease, which the landlord and tenant agreed to, are binding, and cannot be changed except if the landlord and tenant both agree to the change. To the extent that a set of "community rules" is incorporated into a lease, those rules as lease terms can only be changed by mutual agreement. A clause whereby the terms of the lease can be changed without this mutual agreement would be contrary to law, and not enforceable. The law does not grant a resident manager (or landlord) extraordinary powers to override the terms of the lease (nor can the manager change the "community rules", given your description of the lease).

If a landlord wants to evict a tenant, they first have to serve the tenant with a written and signed notice saying what is being demanded, for example, you must pay the rent, or get rid of the pet. If you don't, then in 3 days they ask the court to throw the tenant out. If you do pay the rent (or get rid of the pet), then that's it (for now). If the tenant subsequently violates the lease (gets another dog), landlord can serve the tenant with an unconditional quit notice, and this goes to court. The tenant can answer the complaint (quickly!) and there will be a trial. Then either the landlord or the tenant prevails, and the tenant is or is not evicted. The wise tenant would have an attorney to handle this, assuming that informal persuasion doesn't work. It can be tricky to determine who the actual landlord is (i.e. not the building manager, but some real estate corporation, for example), but you might have some luck looking at the county assessor's map.

The requirement to keep the door closed -- I assume this is an always-locked buzzer set-up -- is actually quite reasonable (it keeps out unauthorized people), but the above legal solution is unreasonable. Interpreted literally, it would prohibit you from having guests (someone would have to open the door!); if one tenant forgets their key and has to call the other to let them back in, that would be a literal violation. The clause does not prohibit you from propping the door open (which would be one of those security issues that I assume they are trying to control), it just prohibits you from doing that for another person. As a literal community "rule", the intent is no doubt to remind people to be vigilant with respect to front door security so that unauthorized persons don't enter, but I don't see any way such a desideratum could be made an enforceable lease term violation of which would justify kicking you out. Possibly a "no-propping and leaving unattended" rule would pass the test of reasonableness.

It has subsequently become unclear to me what the law is about unilateral changes in the terms of a lease. p. 6 of the above pamphlet states that

The lease term, or any other lease provision, can be changed ONLY if both landlord and tenant agree on the change. To avoid squabbles or more serious disagreements, put all changes in writing, signed and dated by both the landlord and tenant. Absent a subsequent agreement to the contrary between the landlord and tenant, all lease provisions remain binding on both landlord and tenant through the entire specified lease term

However, I now think that document is designed for Longmont, and may incorporate local ordinances, may contain wishful thinking, or may rely on uncited case law (or general legal principles) rather than statutes, which are pretty limited. My reading of Title 13 Art. 12 does not reveal any specific language restricting unilateral changes in the terms of a lease. Allowing one party to unilaterally rewrite the terms of an agreement would pretty thoroughly flaut basic principles of contract law.