Yeah I would think the limits are practical - those are kids you have to feed, dress, transport, etc. Also they're all theoretical mini-liabilities in the sense that they can still get the program in trouble with the NCAA (though the chances of that happening are near zero).
Only time this was ever an issue I can recall was when Pitino convinced two players (I think) to give up their schollies and pay their own way so Louisville could have a roster of 15 quality D1 players. Nothing illegal about it, but there was much consternation and gnashing of teeth.
And that was still only about the 1,000th scummiest thing Pitino has done in his coaching career.