Here’s a news story from SecurityInfoWatch’s Security forum that indicates why it’s not a good idea for security guards to sit in their cars.
This happened in Mt. Vernon, N.Y., up the Hudson River from New York City. A gas station was robbed of more than $3,000 while its security guard sat in his car and saw nothing.
It’s pretty elementary, but it’s better to be out and about observing, and getting exercise as well, then sitting stationary and risking missing what’s happening beyond a car’s limited field of vision. Of course, it can be a problem in an area as limited as a gas station and parking lot for a security guard to occupy himself, either sitting or walking. Maybe he could pump gas.