Thats shocking!! I dont care, if i see a speed trap i always warn fellow scoob owners travelling the other way!! I really cant see how they can prosecute a driver for doing this and as you said
"Surely if the guy's forewarning other drivers of a speed trap, then he's only ever likely to cause them to reduce their speed, which supposedly is the point of speed cameras anyway?"
Thats the way i see it, that by flashing its only going to reduce the speed of other drivers.
Another way of getting money off us drivers at the end of the day!!
Joe