What about the recent advice that toilet lids should be closed before flushing to keep bacteria from dispersing around the room? Between that and the knowledge that rats can pop out of the toilet*, I think the closed seat/lid approach is the way to go, backed up by science!
And while we are at it, where do you all stand on those hand dryer/blower thingies that apparently spread poop bacteria all over your hands? At the risk of sounding OCD, I now keep a couple of paper towels tucked in my handbag and in my jacket pockets.

* I saw this on a documentary, and it definitely fell into the category of things I wished I could unsee.