No way that a ride over the sea, on a bang seat would ever be entertained without authority and a medical and a briefing on dinghy drill etc
But what about 'needs must'? As a Sgt ATechA at Valley on Gnat Rects in the Gaydon Hangar, I was called into the office on Friday lunchtime to be told I was being sent to Macrahanish asap to sort out one of our Gnats (XT....) that was there on a landaway exercise. The student pilot had managed during his turnround checks to top up the hyd reservoir with OX-38 - doh! Instructions had been passed (supposedly) that he was to remain there someone arrived to drain, flush & refill. That would be me...
Mode of transport? Back seat, of course. Never having flown in a fast-jet, and being aware of some height / leg length restriction in Gnats, I queried the safety aspect (6' 3" with very long legs) and whether or not I might find myself leaving my knee caps behind should the worst happen. The response left no doubt - " go get yourself kitted out". The office window looked out over the pan and as the conversation came to a halt, I asked to be reminded of the a/c number and on hearing it I said (with relief) "problem solved, Sir. It has just taxied past!