That logic is one of wishful thinking, personally I don't like leaving anything I don't have to down to chance, and I would advise others not to as well. Do you leave your car door open because it's easier than locking it? Or maybe your front door? Or not wear seat belt because it's quicker? 9 times out of 10, zipper suitcases are opened because they can be opened in less than 10 seconds by anyone with a biro pen without even being noticed.

More importantly, thieving foreign baggage handlers can can reseale the zip just as fast without anyone knowing it's been opened - including yourself! And God forbid someone uses your suitcase to smuggle their drugs. It might be rare but it happens, fact. Some countries carry the death penalty for drug offences, or worse, a lengthy prison sentence in a place that would make Britain's worst prison look like a 5* hotel in comparison. And they don't care if you did it or not either, you're lucky if you get a 2 day trial in some places. Prices for clasp suitcases are pretty much the same as a decent zipper suitcase, and it really isn't a big hassle when you consider the risk of alternative.