I mean, is it actually illegal to add terms to the settlement that require some party to (essentially) promise not to go back to doing the thing? It seems like

I mean, is it actually illegal to add terms to the settlement that require some party to (essentially) promise not to go back to doing the thing? It seems like it follows the same principles as non-compete stipulations that come with certain forms of severance, right? I think those often take the form of "we'll pay you this severance, and in return you'll agree to not work in the industry for a couple years". Or am I just uninformed and those are illegal, too?