Lady M: "Cro, can you give me a hand setting the combination lock on my new flight case?"
Cro: "OK, but you know what I'm like with hi-tech wizardry".
Lady M: "In which case you'd better look at the instructions".
Cro: "Looks easy enough".
At this point Cro sets required secret number, fiddles with small plastic bits, turns keys, and sits back, satisfied with a job well done.
Then, of course, the bloody thing won't re-open. We try everything, but it's locked solid, and the new combination numbers refuse to accept that they have any relationship to the wretched suitcase whatsoever. It's a bloody disaster. We stare at it in disbelief.
Cro: "I think I've got the answer. The Irish screwdriver".
Lady M: "If you must!".
A swift blow to the lock with a heavy bolster, and it flies open. We both cheer. I saw off the locking device, paint any scuffed bits with black paint, and return it to Lady M who is perfectly satisfied that it now locks simply with a key; and no stupid combination number to worry about.
It's what any experienced airport baggage handler would have done whilst no-one was looking!