I thought that was a really good clip to watch, and I've also found some of the other ones they have done that are on Youtube too. I think it's good we can see these people in everyday life that will stand up for gay couples, teens, parents etc.
This reminds me somewhat of an experiment that a programme in the UK did called the Tonight programme and a gay couple walked down the high street of a northern city, Hull I believe, and al they got was homophobic slurs.
Good on those people in the diner for being so open minded (except that guy who gave the waitress a thumbs up )
(oh and I also agree with Lacey, that guy was nice )