"Software without tests should be assumed to not work" is true in real life as well. If an external company tried to enter the building periodically and the security guards review included these tests, it would change.
People end up waiting to cross the border for hours on end.
I imagine security guards at a high traffic building have similar leverage and reasons to be lax. When a few hundred or thousand people have to get in through the lobby every morning in the span of 1 hour ... well I think most people would say "You know what, the probability of something bad happening and the consequence if it does is so low that we'd prefer convenience than standing in line for 3 hours to get to work"