Why do customers lie?

[Robotstar5]

Most of the lies at work come from the Fork lift truck drivers, got a call last week to an automatic door not working, found one of the PE (photoelectric) sensors complete with its 100mm heavy gauge channel protection lying on the floor. Now I'd mounted it to the wall with 4 off M12 anchor bolts a couple of years ago between a couple of RSJ's concreted into the floor but they'd still managed to rip it out.
None of the drivers knew anything about it!!