Two decades ago I attended a lecture on bombs and security staged by the airline I'd just joined, AirUK. The lecturer told us how one day he'd been asked to open his case at the security desk of a UK business who'd hired him to advise their staff on bomb threats. The case was full of demonstration stuff: timers, fake semtex etc. The "last line of defence" security muppet in reception asked him to open the case, inspected the contents, closed the lid and handed it back to him, saying "thank you, that's fine. You can't be to careful these days, can you sir?"