Hazard: The receptacle can accept plugs for either 120 or 240 volt products. A potential fire or shock hazard exists if the receptacle is not wired to match the voltage rating of the device plugged into the receptacle.
A major point of the differing plug and socket patterns is to prevent voltage mismatch mistakes. Most 120V loads will get really unhappy with 250V, and the results will not be good...
If the load is a switching power supply that can take 100 to 250V you'd get away with it, but more traditional loads will be severely damaged.
