How about bombs?
Not only do they have a flashing red LED, but it seems that they also come equipped with an audible 'beep' too, just in case the flashing red light didn't give the location away. Hell, even the ones with nothing but a countdown display issue the 'beep'!
and the bombmaker ALWAYS conforms to the red/blue wire, if I were making a bomb, i'd use black wires for everything, just to annoy the bomb squad or make sure the "hero" I target was colourblind >.>