"certainly you can afford more than $1 as a tip. You're not that type of customer. we know you like to treat the ladies special And you can afford it so put a 20 in there instead"

and businessman with ties around their foreheads would stumble to the stage hooting and hollering pulling $20 bills out of their pockets

while the plumber looked around the room, peaked down to count the money in his wallet, and got up and walked to the stage with a $20 bill as well

He didn't want to look like the only broke cheap bum in the entire goddamn clu

get it?
It was really all about psychology