The thing with pampas grass is that that it looks really good ...on the pampas. I, too, thought it a terribly suburban, naff plant until I saw a lot of them together at Kew, and realise they are much more butch plants than we usually give them credit for. They are supposed to be seen, growing majestically high, on the wide open pampas, not in the middle of an eight-foot-square front lawn in Penge.
OP, if you have seen pictures of your prospective partners-for-the-evening and like what you see, go for it. If not, don't. If you do decide to go for it, for goodness sake, remember you can back out at any time - you owe nobody anything, and if you want to put your pants back on and run, don't let someone else's disappointment stop you. It wouldn't be for me, as I am tediously monogamous, but if everyone is a consenting adult I can't see the harm in it.
And the rest of you laughing at older people having sex - oh ffs, why shouldn't they?