In Spain we have just under 3k users. That means some users will want to train the best player possible either buying 18 year old players or just by having luck in the draft.
Lets take the example of our starting SF, Bañales. The manager wanted to make a couple a once in a generation player and he bought a very good 19 yo player:
Transfer 9/20/2009 10 Purchased from kindong hearts for $ 3 000 000
Trained him until he has 28yo, he was on track of making him the best in BB, on the way the player help him promote from Div V to Div III. But all his hopes were shattered when Bañales capped. He was a very good player, but not the best as was his goal. So demoraliced and after 20 seasons of playing the game he quit.
20 seasons of playing are a lot, that is 2007. The guy was just tired and he quit, Bañales went FA and that would have been the end of the player in your system. Why should all NT fans in Spain pay for a couple of cheaters. If you are worried about cheating talk about sabotage. I am in favour of 2x tv revenue rule to help avoid sabotage, but Free agents not allowed in NT teams is not a well thought solution as a big porcentage of the bb-players go free agent in some point of their bb-carreers.