You do not tip the regular Disney bus drivers, but a pleasant 'good morning' as you hop on and a nice 'thank-you' when you get off are appreciated, I'm sure.
As far as the DME bus drivers, that's a whole different story. If the driver loads your bags, and then unloads them, for you..yes, a tip is in order. About $1 per bag. If you have only a carryon bag, that you have kept with you on the bus, then no, you do not have to tip the driver. However, I have had bus drivers with DME that were truly wonderful, and just made the ride so enjoyable that I tipped them even though I had no bags at all!!!
It's almost funny to see those people, taking their bags from the driver, and then trying not to make any eye contact with the driver, or anyone else for that matter, as they hustle away, leaving no tip...while a few, and I do mean a few, give the driver a tip. It almost seems that they know they should but figure that they can get away with not handing out $5, so why bother.
Any time anyone touches your luggage, it entitles them to a tip, basically speaking. The only time this doesn't apply is when bell services brings your luggage to your room, from the DME truck. Their tip has already been figured in....of course, I forgot and tipped anyway!! Now, if your luggage is with you, under the bus, and you have someone bring it to your room for you, then that person does get tipped.
This is all, most likely, clear as mud, but I hope you get some of it...if not, just ask away.
