Do you not have one of those speedcam warning gizmos?
No
You could get her an InfoRad K2. The ideal detector for anyone that does not watch Top Gear
It's small, only about £30 and
effin deafening if you are above the speed limit near a camera. I threw mine (actually a K1) in a cupboard for it's ear splitting intolerance of my 10% over should be OK driving style.
The PocketGPS world web site has stacks of reviews of them and the like