One of the problems with this is that the debate rules are not enforced. If you go back and watch Trump in previous debates he continually ignores the time limits and talks over the moderator when told his time is up. Microphones for both participants should automatically shut off when the speaker's time is up.

Also, obvious, outright lies should earn a microphone cutoff although this would be dependent on a moderator that would be acceptable to both debaters. I can't see Trump ever agreeing to live fact checking during a debate.

Additionally, Trump appears to be even less mentally capable than he was in the previous debates - I do not believe it would end well for him.