All the grounds in your house wiring end on the same bus bar in your panel! The adaptors or "cheaters" have a green loop on them where you are supposed to screw the plate cover screw to ground them for a correct installation. If you kill the circuit you can pull the outlet out of the box and verify the ground wire is still connected. The other thig is to go into the electrical panel and carefully check and make sure the ground connections are tight. The panel ground is supposed to be wired to the water pipe, in older installations, and in newer installations the water pipe and a ground rod. Jim