your conference, where you make the rules. The only exception I've seen is the ACC, and their one out of conference must be in that state. Again they have a little more control.

I imagine they can set rules and regulations about testing for players prior to games, and if/when a game has to be canceled, it's also much easier to cancel a conference game because you don't have a payout to the other team if you cancel it last minute.

Those are my guesses.