Betting pool on when the dad will pull the teenager out of the con.
Relative times are allowed.
Betting on the same time as someone else is allowed; all winners split the pool.
Betting on multiple times is allowed (you win your own money from the other times).
Whoever is closest wins all money up to the time they won on. Everything else should be handed to the teenager as they leave, if it all possible. If not, the remainder is given to the winner, who should try to pass it on to the teenager as able.
At 09:00 Sunday, if they're still there, all money goes to the teenager. Call it an education fund.
Ordered by time.