I actually have a video of my wife when she was in her mid 20's "tipping" a black guy and a Hispanic guy that had just delivered a sofa to her sister's apartment. I originally recorded it with a super 8 camera, then it was transferred to VHS tape and I rerecorded onto a DVD. If I can ever figure out how to edit it and upload it, I would enjoy sharing it to show how my wife would "tip" men that did a service for her.
Oh, by the way the super 8 camera belonged to my grandparents - if they only knew some of the things that we recorded with it, I'm sure that we would have been asked to return it and then we wouldn't be able to use it after that. GTR