Man, it's good to have a cop in the forum - straight answers, direct from the source.
As for what they were doing, it really seems like they were testing. Not sure if they'd have uniformed officers doing such, but I really don't know enough to be able to comment on that one.
Michael's right about the technology though - something has to be emitted, bounced off the moving object, and detected (and therefore measured). If the emitting device can detect it, then something else (ie: a radar detector) can and will be built to do just that.
Bottom line is that it's a cat-and-mouse game. The authorities have to stay ahead of the bad guys, and the market has to keep up with emerging technology. If there is something new, there will soon be something to combat it, and then there will be something new to out-do that, and the circle will continue.