This.

Every company I’ve ever worked at, and that includes very large ones, will have legal, HR, and finance tell you at some point that “you must do X”. Sometimes X is no big deal and you do it. Sometimes it’s hard, and you ask the business to fund it or remove the requirement. Sometimes it’s nonsensical in your context and at that point the job becomes understanding why X is a requirement and how you can satisfy that requirement in some more pragmatic way.

At the end of the day, these functions are there to support the business.

I had an employer that, once or twice a year would send out mandatory agreements we were "required" to sign-- under threat of dismissal. (I don't think this was legal at all).

One day they sent out a particularly onerous "agreement" that said that we agreed not to use a phone while driving a car and doing so would be cause for termination etc.

I went down to HR and asked them if they were really trying to regulate what I was doing in my personal vehicle with my personal phone and they replied "No, its only meant for when you're in a company vehicle or using a company phone."

But the agreement itself clearly stated any phone any car.

The workaround I came up with was this-- a friend of mine and I swapped forms, and signed each others names. HR had their illegal, unenforceable agreement, and life moved on.

I got my "revenge" 6 months or so later. HR was frantically calling me for some reason-- I was stuck on the freeway as is our custom in Orange County. I ignored them for something like two hours, and explained that "I was stuck in traffic and as they were no doubt aware, we are prohibited by company policy from using our phones while operating a vehicle."

The HR gal was visibly pissed off, but to be fair, I could have been fired for answering that phone call.

You're in the US --- California, to boot. I'm not sure what you accomplished by making the agreement "unenforceable", as your employer does not need to secure your agreement to terminate you for virtually any reason. Discovering that you text and drive in your spare time, off hours, is something they'll likely have no trouble firing you for, unless you have an employee contract that somehow gives you tenure except for for-cause hiring (almost nobody has one of those).

Perhaps I didn't explain myself well.

I am not a lawyer, obviously, but what I meant was, threatening someone to sign a legal document can't be legal, even if its your employer.

Sure it can? All sorts of jobs are contingent on signing contracts (NDAs, acceptable use policies, background check authorizations). Why would you think it wouldn't be legal? The "threat" is simply to stop employing you, which your employed (in the US) has an almost absolute right to do anyways.

Where's the line then? What could they "force" me to sign and what couldn't they, in your opinion?