A big lump of (optical) machinery needed transporting across the water. Enter 1 Herc plus crew. Machinery looked a little lost hiding in a corner of said Herc, so an unnamed Neddy decided to send a bunch of things that go bang as well.
Arrive on the shores of Lough Neagh, land, taxy in.
The mystery men are waiting for their lump, and lorry drivers for their ordnance. Ramp at the back goes down, out trots the (female) loadie. She explains to the head mystery man that he'll have to wait until the fireworks are unloaded, turns to the other waiting customer, and says:-
"Oh - here are the pins" and hands him 20 pins all with pretty streamers attached.
"WTF did you pull them out for?"
"Well, the streamers say 'Remove Before Flight' so I did!"
Customer turns very pale. Sends for armourer who turns up, has situation explained to him, gives loadie a withering look and, trying to prevent knees knocking too much, enters Herc and (very carefully) reinserts pins.
No doubt the flight crew are by this time very very pleased it was a good landing!
As I heard the story, the loadie was merely "retrained", having not been trained to deal with this sort of cargo, and is still flying.