I think checking employees bags does one important thing, it keeps honest employees honest. You would hope that their morals would do that but some people get tempted.
Like most locks and laws they keep the honest, honest. If someone wants to break a law or get into a locked place nothing is going to stop them. It is just a road block.
The say the average car theif can get into a locked car in less than 10 seconds.
Sad, but in today's society that seems to be the way it is. There is always some news story about someone robbing a bank, shoplifting, ect. something they never ever did before but in thier minds desperation, well you know.