I've had to sign many of them. The only one that would have definitely been enforced was not tech-related and very narrow in scope (don't open competition within 10 miles).

But every tech-related one amounted to, "you're not allowed to work if you sign this". I didn't have any "issues" with them, in the sense that nobody ever tried to enforce one, but it's still a load of BS that we shouldn't need to deal with.

Non-compete agreements for employees are a farce, IMHO.