The Herald-Sun reported today that the police association, as part of its pay dispute with the state government, might recommend its members park police cars next to speed cameras —sorry...road safety cameras! — to warn motorists.
(It reminds me of the robot in Lost in Space shouting, "Warning! Warning! Aliens approaching!")
I have no idea if this will come to pass, but it provided me with the perfect segue for a short post I've been intending to write for a while, spurred on by the recent media coverage that a decamping degustater was not hindering or obstructing police.
There's a mix of cases about warning motorists of police speed traps on the road ahead, and whether that's an offence or not.
The first is Betts v Stevens  1 KB 1. Mr Betts was employed by the Automobile Association — the UK equivalent of the RACV. He stood next to police, armed with stop watches to time cars over a set distance, and warned cars with an AA badge on them they might be speeding. Those cars slowed down and avoided being stopped for speeding. The Kings Bench unanimously found the appellant had obstructed the police officers in the execution of their duty.
Similarly, in Patch v Ebbage; Ex parte Patch  St R Qd 32 the Queensland Full Court held that a taxi driver who called out to approaching drivers to warn them of a speed trap was guilty of obstructing a member of the police force.
But in Young v Owen (1972) 19 FLR 70 the NT Supreme Court considered these cases and several others to conclude that warning other motorists police were ahead (in that case, with an amphometer) did not constitute hindering police unless an offence was being committed, and there was some concert between the warner and the warned, or the police were executing a specific statutory duty. It seems then that a general caution or warning to the world at large isn't hindering or obstructing police.
(Of course, should Victorian police decide to warn motorists of the presence of speed cameras, not only may there not be many complaints, but since the cameras are now contracted out to Serco, they're not staffed by police in any event.)