We might have been packing a powder puff at the perimeter, but I can assure you our US collagues weren't titting about. - Or perhaps they were..
My Brother in law was USMC at a certain 'Facility' in the South West and got a visit from a pal at his Quarter just off Dustbin Alley. To cut a long story short, the chap left a grenade down the side of the settee.
BIL panicked.. and not wanting to dob his buddy in, discharged the granade off the cornish cliffs.. Sometime later the Yanks discover 'One of our granades is missing' the guilty bootneck coughs and says he's left it at BIL's house.. They drag him in, and he comes up with the unlikely but true story of how he disposed of it and subsequently was busted to PFC.
Yes they were definately armed AND dangerous.
Although the thing that tickles me about the disposal, was that although off duty, he got dressed up in his battle kit to throw it off the cliff..