A danger here to note when consulting with a company that retains the license, is that the engagement could be terminated with very little warning upon simple threat of action to be taken. Legal action itself is less imposing than an email with the threat of legal action to many companies.
And so the the various points about action taken against the consultant - it is far more likely they will exercise some measure against the holder of the license, the company. Losing the right or access to use the software could be a significant business impact.
I've been in the precise situation before, where I am doing nothing wrong (as the consultant) and the company is doing nothing wrong (just getting help/support/training/etc that the software company cant provide) ... and the engagement comes to an abrupt end because of the threat of litigation against the company. (another clause to be wary of is a 'use of software' limitation or 'intended use of' the product restriction)
In these consulting cases, I have done a diligent and careful review of contracts and terms and there is no legal basis for a claim - no case. But that does not prevent the threat of legal action or revocation of license which is quite often, more than enough for a company to end an engagement.
Therefore, the ability to enforce the term isn't necessarily the point of the clause. The ability to point to it when making a claim, and deter through threat of filing with a simple letter are more likely the point and purpose.
Always be sure to be upfront with the company about the known risks involved. Depending on the size and type of business, I have found they will often choose to engage services regardless, if there is enough value to them.
Can a software company forbid individuals to consult on how to use their software in the United States?
While there are multiple facets to this (consultant vs employee vs company) the software company in question can restrict the use of the software but not individuals that aren't under the scope of any agreement. They cannot act in typical circumstance outside existing law of the relevant venue. They are free to threaten frivolous lawsuits all they wish, however...