You do not have to be in your room for bag delivery. There is no 'extra' tipping to be done. Everyone has already been tipped...that's one of the perks of using DME. Now, as far as the driver goes...if the driver handles any bag for you, you should tip him. If you have a carryon bag that you had the driver place underneath the bus, he gets $1 per bag. But, if you just boarded the bus, with your carryon with you, no tip is required.
I have tipped a driver before who never touched my bag..he was just a terrific driver. AND....he did not ask for a tip!!! Every driver since then has actually said that gratuities are greatly appreciated. That turns me off..there is already a sign right beside the driver that tells you this...I don't need the driver telling me also. If they ask for a tip, they don't get one!!!