If-Off-Stay-Off Box, power loss safety device

The if-off-stay-off box is a cheap tool for protecting electro-mechanical devices from damaging themselves following a power outage by preventing them from turning back on when the power returns. If the if-off-stay-off is unplugged and re-plugged in then it will remain OFF until the button is pressed (then it will remain ON until unplugged again). I designed this for a friend who was worried about his fish tank filter pump, which needed manual priming to operate properly and would be damaged if allowed to run dry (which would happen following a power outage). Of course an uninterruptible power supply (UPS) is the preferred option for protecting devices during a power outage, but they also cost about $60. Perhaps you can think of alternatives uses for this device anyway; Practical jokes maybe?