One thing you have to consider when people are zonked with live animals: Its value. I remember a foreward Monty Hall wrote for Marla Schramm-Schwartz's book "How to Get on a Game Show and Win!"
In it, he talks about the one guy who was zonked with an elephant, was offered a chance for the Big Deal (which he declined), and insisted on keeping it. According to FCC regulations, whatever was presented to the contestant, they had to take it.
Normally, the people at Hatos-Hall Productions would have 'Zonked' contestants sign an affadavit of forfeiture and accept a reasonable prize (such as a TV, Stereo, Refrigerator, etc.) in return.
As for the guy who wanted the elephant, Monty had to shell out $30,000 to the person, in exchange for the animal--as it was the going rate then.