Bad guy is easily defeated. "I'm sorry, I've accidentally spoiled my ballot and marked the wrong candidate, may I have a new one to fill?" Bad guy's ballot goes

Bad guy is easily defeated. "I'm sorry, I've accidentally spoiled my ballot and marked the wrong candidate, may I have a new one to fill?" Bad guy's ballot goes in the trash, you fill the spare new one, you still have the original blank one to hand back to him. Bad guy wasted his time.