Not sure when or on how many occasions but almost certainly on business trip.
It came up in conversation last night, not sure how but for some reason I asked him whether he had ever been and his reaction was 'of course'
He is a 48 year old, highly educated married man with 4 children including a daughter who is late teens.
I can understand that on business trips it would be easy to feel under pressure to follow the crowd ( in his case, a large group of predominantly male, middle aged engineers) but it still bothers me and his casual reaction to it bothers me even more.