I regularly get thumbs up from cops in my city. It's not a small city, either. Even one or two thumbs up from the outlying suburban "Speed Trap" city. I'm far from inconspicuous, too. Heck, one even rolled his window down at the stop light and wanted to compare notes; apparently he had a modded 350 lol.
Point being...don't lump all cops into the same group, cuz they're not. Some are bullish, some aren't.
On one of the nights I got a thumbs up on the interstate, it was from a cop who paced me for just long enough to make sure I saw his appreciation. You know what else was happening? There was another cop riding my bumper, who'd been there since I turned onto the interstate, and stayed there until I got off ---- nearly 11 miles. The thumbs up cop was clearly amused at the bumper riding cop.
I'm not upset...these things happen when you drive a car like ours, especially when you make it stand out. As long as I'm not giving him/her any reason to stop me, (s)he can tail me all they want; I consider it an escort