Sorry, Andy, I thought this was more of a continuation of the first question, rather than a new one.
It's true that the DVD players at these venues are plugged into something (duh), but you'd be surprised how often it's built into some pulpit or hardwood cabinet with less-than-convenient access. These swanky reception halls are set up for people to easily plug in their AV devices; it's very rare to have practical access to the AV ports. Sometimes we'll do a wedding with the reception at a conference center-type place, which tends to be more AV-friendly, but more often it's a nice restaurant, a hotel, a golf club, etc.... Blu-Ray may or may not ever become the next standard, and there's a definite demand for fast DVD encoding.
Thanks for your help!
http://www.vimeo.com/gwg