[QUOTE=tsastor;8488697]By offering extra money you are implying that the service you received was made expecting money in return. Many people outside of the U.S. may find this insulting. I would try to tip as discreetly as possible, like saying keep the change or (in a restaurant) leaving the tip on the table. QUOTE]

The Texas supermarket chain where I shop, HEB, does not allow its "Bagboys/girls"/cart attendants, almost all high school and college students, to accept tips for assistance in carryout, loading groceries in a vehicle, etc. I routinely see "folks from far away" go through gyrations trying to tip, since they are obviously used to gratuities for this type of service.

On the other hand, my favorite local restaurant, Siete Mares, a Mexican seafood joint, has a parking lot attendant who directs entering vehicles, a la the ramp man at the airport, then stands guard in what might best be described asa "less than desirable neighborhood". I believe that most of the patrons (Now, there'sa Freudian slip) routinely exchange greetings - in Spanish - on arrival and tip a buck or two when departing, just as we grew up accustomed to when visiting resturants and clubs in "Bordertowns". I do not expect that the incumbent, his predecessors or successors are likely equipped with the full range of documentation required for residence in the US.