Dont call it Chivalry. Call it decency. Is a man on a date nothing more than a taxi driver, to drop off his fare at the curb and drive away? Should he perhaps yell from the car, “good night”? Should he sit in the car like a bus monitor waiting for the door to open and she gets inside? the couple has spent the last 3-4 hours talking about who knows what, suddenly it is not tznius to walk the girl to the front door, say thank you it was a pleasant evening and good night?
If it is not tzniusdik to walk a girl to her front door, after spending 3-4 hours talking in a darkened lounge, walking in the park (where there may be issues of yichud) then perhaps sit ins would be more appropriate with parents sitting in the next room?
Pool and pool halls have a certain stigma attached to them because of the imafe that comes to mind when it is mentioned. There are many dignified Billiard rooms one can attend. A hotel lounge is essentially a dignified bar.
Instead of saying stupid things like ” this is assur, not tznius”, this is assur not “torahdik”, this is muttar because it is appropriate think about the situation. Not every hotel lobby/lounge is appropiate and not every Billiard room/pool hall is inappropiate.