What I suggest and practice is the use of no less than 2 recorders, (I carry 3) and keeping it no secret that one
of the recorders is in use, with the secret one being deep in a pocket or one of the spy button, pen, watch or similar type recorders.
I suggest declaring the out in the open recorder, because this gets at least 70% of non OC friendly cops to be on better behavior. But the lesser police we have seen have been known to snatch the recorder and shut it off while violating your other rights.
My theory is that if the main recorder gets them to increase their good behaior, good. If it gets them to snatch it, that's an unlawful seizure in gross violation of state and federal laws, and I want audio and video of that, not to mention the unlawful terry stop I'd be the subject of.
I'm no lawyer, but whether or not you get the consent of a criminal to video tape him or her victimizing you shouldn't mean much, whether it's public and consented to or not.