Another reason to carry a double adapter, if required you can ask to plug your device in beside theirs or you can be the good guy and offer a spare power point.
Mine has a surge protector just in case.
+1. Carry a mini power strip with 3 outlets + 2 USB ports. Never had anyone object to letting me plug it in somewhere and sharing. Also great for hotel rooms that leave all of 1-2 empty outlets.