People are very odd, Stella... having dealt with a number of bizarre luggage incidents at airports, if they have said they are not treating is as a terrorist incident, I am entirely happy that some numpty did something spectacularly odd, that makes no sense to anyone else, but that in their own head made perfect sense (I can't be bothered to carry my case while I get lunch and it won't fit in a locker, so I'm going to use my bike lock and leave it here, and wrap all this cable wire round it so no one can nick anything)
I've had security incidents sparked by a hairdryer and a perfume bottle (it was cut glass but apparently 'shaped like a grenade' - er, no it wasn't. It was a perfectly normal perfume bottle) so I have a very high tolerance for this stuff (am also old enough to remember being evacuated from work on what seemed like a weekly basis after hoaxes etc).
The sensible tolerance level is probably somewhere between us 
I'm definitely not saying that we shouldn't take suspicious objects or threats seriously, but if I had a pound for every evacuation caused by someone's luggage, I wouldn't be on my way to work now.
Fingers crossed we all stay safe over the summer x