Nope, provisions for that are in M&A agreements and part of the reason why acquiring companies takes so much money and [lawyer]time. And it's in no way a "precedent based on this law" - what do you mean by "this law"? All of these provisions are in private contracts, not in legislation.

The classic use of non-competes is for salespeople or high-level service people (lawyers, consultants, etc) not taking their customers with them when leaving.