I am in the middle of my current fixed-term lease and have always had
a mechanical key-based lock on my apartment door. My landlord has
announced that the doors of all apartments will shortly be converted
to electronic "smart locks". The smart-lock maker's website says that
any use of their product constitutes agreement to their terms of
service.
Is the landlord allowed to install this new type of lock? How does
responsibility divide among myself, the landlord, and the smart-lock
maker?
A lease determines the respective rights of the parties, and in the absence of an express allocation of rights and responsibilities, default rules of law, the intent of the parties, custom, and the course of deals of the parties controls.
Typically, in a residential lease, the landlord is responsible for maintaining the structural, mechanical and plumbing parts of the premises, in a manner that may include upgrading them, and the tenant is responsible for keeping the place clean and not violating lease terms.
Normally, the landlord would have the authority to maintain, repair and replace exterior doors and locks to the premises, including changing the style of lock, with reasonable notice to you, and providing you with the means to use any new lock with a different key or access means, but not requiring your permission.
The landlord, by buying the lock, agrees to the TOS. You are a third-party beneficiary of the TOS between the landlord and the lock company, who probably has standing to enforce TOS against the lock company.
But, you are bound by the landlord's actions, because you are "in privity" with the landlord since you have a contract related to the premises including the door and its lock, with the landlord. Since the structural features of the apartment are delegated to the landlord under the lease, the landlord can act. This is similar to, but not quite identical, irrevocably designating the landlord as your agent with respect to these matters under the lease (and in some leases, the landlord would be expressly designated to be your agent with respect to some or all matters).
In the same way, the landlord decides without your input, what kind of carpet to use in the hallway, what kind of lock to put on the front door to the building, and what kind of roofing singles to use. In many multi-family buildings, the landlord even decides what the internal temperature of the building will be and there is not an individually controlled thermostat for each unit.
What are my rights and how can I assert them?
Since the landlord is vested with discretion to carry out this part of the lease, the landlord has a duty to exercise this discretion in a manner consistent with the landlord's duty of good faith and fair dealing, and to comply with all applicable federal, state and local laws and the "hard terms" of the lease in doing so. But, unless the lease expressly provides that door locks are the tenant's responsibility or that you have a right to a particular kind of door lock, the landlord has the authority to change the door lock type even though it is accompanied by a TOS.
If I cannot prevent the smart-lock installation, can I somehow
establish that I am not bound by the terms of service despite what the
smart-lock maker's website says? Would I simply wait until such time
(if ever) that I have a dispute with the smart-lock maker, and then
use my non-consent to argue that the terms neither protect them nor
bind me?
You cannot prevent the smart-lock installation.
While you are discussing the TOS in the abstract, it isn't obvious what specific prevision of the TOS you are concerned about and the issue would depend in part on what term was at issue and how it presents.
You probably do not have liability to pay a service fee on a contract that the landlord entered into and you did not, in addition to your rent, and if you were bound for some reason to do so (e.g. the landlord didn't pay and the smart-lock firm locked you out until you paid), you could probably deduct that payment from your rent with notice to the landlord that you were doing so.
Realistically, the main parts of the TOS probably waive the smart-lock company's liability for wrongful entry to the property or for harm caused by its malfunction, to the full extent permitted by law, and probably contains some privacy waivers. The waivers of liability to the smart-lock company don't relieve the landlord from liability to you for defects or problems with a product installed by the landlord.
The privacy waivers probably do bind you, and are basically comparable to a lobby security camera or a doorman level of privacy invasion, so you probably have no remedy there.
How strong would that argument be, and what if anything should I do
now to document that non-consent?
As noted above, you don't have a very strong position, although you aren't entirely without rights. It wouldn't hurt for you to at least ask the landlord, in writing, to hold off on replacing your lock until your lease ends and to outline your concerns. You can't insist, but nothing prevents you from asking, and this would also show a lack of voluntary consent on your part. There is really nothing to be gained from communicating directly with the smart-lock company (unless the TOS or a California privacy law gives you an express right to opt out of data collection by affirmatively doing something). You could also read the TOS to see if there are other options you can elect, but there probably aren't.