Originally Posted by
blauger
I would be concerned with it overheating and the possibility of it being damaged would be greater than if it was in the pack. ... ...
I carried my 7 inch tablet in a neoprene foam sleeve made out of the stuff that scuba divers use for wet suits. I then put that in a plastic box (with the cables, etc.), the plastic box was intended to prevent something from cracking the screen. I think I paid 69 cents for the box on sale at Walgreens, it was sold as a pencil box in the school supplies area. The box is not strong enough to stand on, but it is robust enough to protect the tablet in a pannier and is quite lightweight.
Have Ortlieb panniers so I did not need a separate waterproof cover, but if I did not pack it in a water proof pannier I would have also had a small drybag to put it in. I carry a small drybag in my handlebar bag in case of rain for my camera.