Ive never worked a job where I had to sign a non-compete, but I do remember when I was playing in a band a lot of venues in bigger cities (big enough to have actual contracts with their gigs) included some kind of language prohibiting you from performing within a certain radius of the venue, usually like 50 miles, for a certain period before and after the date of your gig. I imagine those kinds of contracts would not fall under the same category since as performers you arent actually employed by either the venue or the promoter.
(he/him)
"The hopeless don't revolt, because revolution is an act of hope."