Nope. It might even be illegal to offer a cash alternative. There are lots of complex laws around what companies can do, must do, and can't do with respect to healthcare.
you can negotiate your way to anything you want. while companies technically might have laws to comply, it is on the employee to negotiate their way into whatever it is that they desire.
for instance, I may be negotiating my salary and get to mutually-agreeable amount X. I can then say I do not want to be covered by your health insurance but in lieu of that I need my salary to be X+$30,000 to cover the cost of the health insurance I will purchase myself for my family. the company of course can say yay or nay on that but this is the avenue one can explore to get around this company-provided-HI nonsense.
