Just buy some of these:

http://www.amazingmagnets.com/index....PROD&ProdID=74

Glue one on the top and bottom to the inside, and one on the top and bottom of the lid. Believe me-- they'll keep the lid on no matter how hard anyone pulls a plug out of the socket.

Only one problem: you might have to make a hook out of a coat hanger or something to pull the lid off (just stick it through the socket hole.) Other than that, though, you'll be good to go.