My general rule with my son was that you don't put kids into situations where it's impossible (given their level of maturity) to behave reasonably. That's why you don't take 3-year olds to the opera, for example. We never had the opportunity to use a hotel lounge, but if he couldn't sit still I would have picked up my coffee and taken a walk around the lounge with him. And if he wouldn't stay quiet, we'd be outta there. He learned quickly, and was generally well-behaved when he had to be.

One of my favorite hotel lounge memories was the Cardiff Hilton, right across the street from the castle with a magnificent view. Although the staff worked hard to keep it tidy, there were usualy small fingerprints at kid level on the windows facing the castle. I thought it was cute.

I agree, Joe- the hotel that banned kids from the lounge in the evening but allowed noisy, raucous behavior form drunken adults was just plain hypocritical. We also stayed in a hotel in which a couple of women (plus 4 kids) took over the small lounge and treated it as their living room. Boorish behavior occurs at all ages.