In the early seventies 'black light' the infra red version of Nightsun was introduced. It required trialling before it could be released to service so it had to be flown and operated extensively in the dark.
This was in the middle of July in Southern England.
We would take off at about 23.00hrs and head south from Odiham towards the downs and the coast to avoid street lights etc. The RHS pilot and operating crewman would be on goggles and the LHS safety pilot would monitor what the helicopter was doing.
The number of times the random scanning would pick up a couple in embarrassing positions were uncountable and the crewman and RHS pilot would be goggling the scene with the LHS pilot pleading to have a go at the goggles.
Meanwhile down below.
"There's a helicopter up there!"
"Don't worry, they can't see anything; it's dark."