OK I actually got a chance to try this fining theory out.
I had a young AM/F on my reserve side in his last year of a contract. He was picked up by another team late in the season. The transfer was to go through in June and I was due a much needed 7,000 pounds.
Well this guy gives me a parting shot stating his reason for moving was conflict with the manager. Now for the good part. The other team could not afford the transfer fee and asked to postpone for a week. No problem I replied and promptly fined the player a week's wages for unprofessional behaviour. He was upset and shocked at the fine.
He was even more shocked the next week when I was asked for another week's extention and fined him again.
No support from the players, but no backlash. They probably weren't sure who he was either.
Turns out the deal fell through and I free transfered him out.
I've now been baptised into the wonderful world of fining. That 100,000 debt is as good as gone.