So thiscame up as a comment in the pub at the weekend, that in the 70's if there was pampas grass in the front garden that meant the residents were swingers. I'm sure I've heard this somewhere before (prob on here tbh) but was it true?

And if so how did it work? Random knock on the door - 'Hello we were just passing and saw your pampas grass, fancy some wife swopping?'