I don't know SAS. There are alot dafter things going on out there.
I believe that there is one field where they land after dark with the aid of the local prison lights.
As per say i don't think thier should be a problem if its a unlicensed strip and its only the owners which operate into it at night. If the owners gave permission to someone else to use it you could get problems if anything happens.
People have been landing at night for years and still do with the aid of flares, fires and even a lines of people with torches.
The old halifax pilot i did some retraining with for his NPPL said that it was normal only to have 2 lights one at the begining of the strip and one at the end. The object was not to land before the first one and stop before the second one. And no NGV goggles in them days.
The electronic listening out on a freqency I wouldn't think is a problem. I would use the gliders frequency as its legal for you as an aircraft to transmit on it (even though its a couple of clicks) and its is also allowed to listen to that freq without a license. And gliders shouldn't be airborn after dark so you shouldn't bother anyone.
MJ