I've been in a lot of CLs but only 2 that i remember a jar/plate...one was the SEA airport FS and one was the Schaumburg Marriott...that one may have even had a sign...

i usually tossed in a couple bucks but not always........i don't have a problem tipping-especially someplace where the concierge acts like one, and not just a food replenisher! (not that i am needy, i just think it is nice if they don't hide in the kitchen or yak on the phone...plus the people in those lounges were very nice....i am just not too sure if i think a tip jar is tacky or not.

at the REN Meadowlands in East Rutherford, the male attendant was hiding in back , barely had any food out, opened 15 minutes late on a weekday and was flirting with a little chickadee from the desk....(yup, had to rat him out-sorry)