Before getting carried away recording your favorite LEO's, check your local laws. Chicago has laws on the books making it a crime to record what a cop says, for instance. Sure, you could probably beat it in court, but unless the ACLU offers to handle the case for free and pay your expenses, you could wind up in one of those situations where you are right but you still wind up paying anyway. Life isn't fair, and then we die. If you want to avoid 99.9% of situations that might make that app useful, keep your nose clean and ride/drive within the rules. Regardless of all the gestapo hype you'll find plastered all over the place, the vast majority of LEO's don't have the time or the inclination to make chit up just to screw with you. When you run that light, blast by the radar at 100+ with your straight pipes blaring, etc., it's not a violation of your rights if they pull you over. And if you give them lip, don't be shocked if some give it right back. Dealing with a bunch of doofus's all day can tend to affect how much patience they maintain. Check out how much the average state trooper or local patrol officer gets paid to deal with jerks and potentially lethal types every day, then ask yourself if you would trade places with them.
btw, why would the ACLU promote secretly recording others when they fight against the right of the state to do the same thing? Anyone besides me find this a little strange?
Jerry