A spare set of bulbs, now that is a good idea. If you are ever stopped for a blown bulb, you can either put one in there or then or hopefully a police officer would let you do it home. I'll sort out a set for both cars, thanks.
You would need to check your bulbs everytime you get in a car like a pilots pre flight check - not practical. I think I would prefer the police to speed check oustide schools when the kids are arriving/leaving. I saw many doing 50-60 km/hr oustide my boys school yesterday, some on phones, one drinking from a bottle head back swigging and one other looking down at possibly the radio controls - all whilst speeding.