Winterizing: Holding tanks dry or not?

Here's the deal on this and other procedures we use each year. We somehow learned how to do this and nothing bad has happened to us by doing it this way, so that's how we're going to do it from now on. If something changes (busted pipes, pink ice cubes)then we do some research and find out what we did wrong and change it. Everyone will have an opinion based on the fact that it's the way I've done it and nothing bad has happened. There are, of course, some sound engineering reasons to do certain things, and some of them were mentioned here.

BTW, there are no sound engineering reasons why black tank sensors never read empty :)