If no speeding crime has been committed, then there's no justice to obstruct.
There must first be a crime, then if obstruction of bringing the perp to justice occurs, then there is, obviously, obstruction of justice.
Then again ..
.. If someone speeds and there's no cop there to see it, is it still a crime?
Likewise, if someone trespasses into America and there's no border agent there to see it, did the criminal trespass still occur?
The problem here is that flashing one's lights to warn people who
might have been speeding is tantamount to aiding and abetting a law violator, in essense, "hiding" them from police.
But people do so because of the natural comraderie that develops between most drivers when it comes to the police, police who can take their money away from them. The thought of having one's money taken from them frightens people into protective relationships.
And it's difficult for police to tell who was speeding and slowed down in response to flashing lights and who wasn't speeding in the first place, so without an actual criminal to point to the police can't prove aiding and abetting, even though it was clear that the flashing lights was "likely" an aiding and abetting attempt.
Not sure what the solution is here .. but if the police are frustrated too long on the matter they'll develop improved high-tech methods involving GPS, heat signatures, etc. and the light-flashers will be rendered irrelevant and all perps will get nabbed.
Of course, people could just slow down .. but who wants to be late to work, or to that hot date?
And besides, there are so many traffic jams anymore that when one breaks free from them it just feels so damn good to hit that accelerator and speed up! Someone should do something about the traffic jams!
Regardless, illegal aliens should still be deported, and those Benedict Arnold Americans who aided and abetted them brought to justice, no excuses. Just so it's clear the analogy breaks down compeletely here.
We must choose the laws we will support and those we will violate with respect to what's best for our fellow American citizens.