On a related note. Years ago I was sitting on the board for a kyu exam. We usually have a verbal section depending on the level of the test. Anyway, I listened to the test taker go on seemingly forever about the deep meaning of Onegaishimasu as being this special term about the deep respect you have in asking someone to train with you in the dojo.
Later on some of us went out for dinner at a local sushi restaurant that I frequent much more than I should. I made a point of sitting next to the guy and ordering my beer... "Sumimasen, Sapporo Onegaishimasu.", He immediately looked at me with a confused look but then was even more surprised to hear the waitress say "Okay, one beer coming up...".
A nice example of the americanization of tatemae.