It somehow reminded me of Ian MacKaye during his Fugazi years.
He always had in his pocket several envelopes with cash in them, the cash was equal to the cost of a ticket to the concert.
Each time someone did something he didn't like (which was usually someone trying to act like a violent punk), he would stop the song he was playing and give one of these envelopes to the person in a very polite way and then he asked the person to leave.
He had some sort of "zero tolerance" for bullshit... and his "trick" of the envelopes with cash was good.