I do the same as psychephylax. I tip when travelling for personal travel, but not for business travel. If I am there of my own accord, then I am happy to tip, but if I am there for someone else, I don't feel the urge.

That's probably not fair to the maids, though, especially given all the body hair that ends up in the drain after I shower.

I do leave a tip when travelling for business if I have made a mess that goes beyond a normal cleaning.

Greg