I strongly feel that anytime a team illegally uses a prospect, the team should be penalized and receive zero points for that day.
Thus if a team illegally uses a prospect that is either ineligible given lack of roster space or has surpassed the 82 game mark and not promoted with an Entry Level contract, they score Zero points for the 1 day or 80 days that illegal player was used.
Essentially, it is the responsibility of the owner to manage their assets properly.