Because it is illegal. No need to be a dbag and downvote me because you didnt read my comment properly. Its illegal but not wage fixing and not a cartel.

Actually, I've never down-voted anybody.

Colluding to not recruit between those players sounds like an intent to limit (to some extent) employees options, which would reduce upward pressure on wages.

What would you call that?

Sorry, I assumed 3 comments = 3 downvotes. Anyway, I was just pointing out that it doesn't match any definition of 'cartel' that I can see. However it's still illegal (but not because it's a cartel).