I disagree. I think this is perfectly in the public interest. I also think that perhaps the CPS should peruse other offences with this vigor, but that's a different argument.
You can't say that flashing lights to warn oncoming drivers isn't being obstructive?
Are you joking? Please explain exactly how it's in the public interest? How does punishing this man serve the greater good?
As for being obstructive, of course it bloody isn't. If drivers are slowing down, that's what the scamera was there for in the first place. The only way you can argue it's obstructive is if you admit their only purpose is to catch people out, and to raise money.