Not a terrible idea, but getting people to volunteer for that might prove a little difficult, especially for the late night shifts.

Another thing you may want to consider is hiring a security gaurd or two, especially at like 25 an hour, I'm sure if there are like 50 guys, no one would mind pitching in like 50 cents for a security guard, or 1.00 for two, and so on and so forth.

Later,
Aj