So...one person can get a vote, even a unanimous vote, thrown out with a single spell? Cast charm person on someone voting, then reveal that "someone" has cast a spell to interfere with their vote?
Now, I was thinking that delaying the proceedings to keep the high priests contained at the Godsmoot could be part of a strategy (backup or otherwise), in which case the ruse being detected wouldn't necessarily be a problem; with this sort of "enchanter's filibuster" rule, the ruse being detected would be outright advantageous.