My son had a 180 degree different experience, at i think 15, under nearly identical circumstances! We were at a tournament and he had some issue (can’t remember exactly what, this was many years ago) and I took him to the hotel spa for a therapeutic massage. They made a HUGE fuss over him, and I specifically remember them saying they so rarely saw teenage boys and that most of the massage-seeking gentlemen were much older! I didn’t think much of that comment then, but this thread makes me wonder if there wasn’t some naked room there too somewhere!
Anyway, they whisked my boy right back and he loved it…totally fixed him up for the next day. I agree with OP that, here in America, teenage boys really are not keen on hanging out with a group of naked old men, and if the spa knew it had such clientele in the waiting room (and it certainly SHOULD have known this), it was not appropriate to put the boy there for 15 mins. Sheesh, these days, it seems downright perilous for a business to put an unsuspecting minor in a room with a group of adult naked strangers, even of the same sex, without at least some advance notice or parental consent.

