My wife's career is a specific type of medical technologist, and as such has a specific knowledge and skill set, one that is not transferrable to any tangential career path. (Read: she can only make a living doing this one thing, short of going back to school, apprenticing in a new field, etc.)
She was forced into a non-compete early in her career for a company that ground its employees to dust. When she finally realized the grass was greener and moved on, they sent her a threatening lawyerly letter for working elsewhere. Not for stealing any kind of trade secrets which someone in her role would not be privy to anyway, but simply for trying to make a living in her field, moving on for higher pay and better hours.
She had a panic attack over the threat of a lawsuit that would ruin her, until we ran it by an employment lawyer who laughed at the letter, told us it was completely and utterly unenforceable in our state, and sent the prior employer a nastygram of their own. Well worth the $150 for the relief and satisfaction, to say nothing of never having to receive a threat like that.
I agree with the commenter elsewhere above that this type of law largely has the effect of limiting the movement of labor to the detriment of the laborer and advantage of the employer. Shouldn't there be companies that, you know, attempt to be "competitive" and dislike this type of law because it may keep them from hiring great talent that feels locked up at another employer under legal threat? If I'm a tech entrepreneur looking to start-up in Idaho, I'd not only consider the assumed tax benefits and existing local talent base, but the ability to freely hire them.