Harry is right, in that combat missions they were fused. I didn't know if
Wolf's hypothetical situation included ferry missions, where the bombers carried an internal load just to get them across the pond. I would think they
could do that, if necessary, but for speed and range, they'd leave the bird "slick" and ship the explosives overseas by. . . well, ship.
By and large, they majority were mechanical fuses for GP bombs. I do recall seeing some Prox fuses later on in the War though. I think there were a smattering of intertial base-detonating fuses (I'll have to see if I can dig up my pubs). But yeah, so long as arming wires are in place, life's fairly happy so you can get in and inspect. There were a few cases that arming wires had
broken and slipped out of guides/retention slips--but that was after
years of exposure. Didn't line up the firing train, but gave an EOD tech some cause for concern.
Harry are you prior ordnance?
Tripler
Woooo! Bombs and refills, all in the same thread!