Forgive my ignorance, but isn't the Personal Break timer introduced for this? I never quite understood why SC did not make the PBT just shorter for Legend League and the time to wait before being able to log in again longer. Also, shields should probably removed.
After all that, SC would be able to see in their logs which people are using pilots. I mean if a person is online for the maximum time before BPT kicks in and then logs in again after the wait period and again is online for the maximum PBT time.... that's a clear indication.
Edit: and to add to the original discussion: why o why does no one just use the option not to play. Why do you need SC for your clan management problem? Do not cut in MY playing of Clan Games if YOU do not want to do them. Not doing them is an option after all. No one is forcing you to play the games. SC could make the rewards less "FOMO" like.

