It doesn't matter in a practical sense. How are you going to prove the LEO prevented you from recording? It's your word (as a now suspect of a crime) vs their word, a respected public servant, and their partner, who will swear by them.

Even if you do prove they stopped you from recording, so what? You don't have evidence of your interaction to implicate them. As long as they recite the magical words, that they believed they were in the right, current legal doctrine will look the other way(see Heien vs North Carolina - https://blog.simplejustice.us/2014/12/16/heien-v-north-carol... - and similar).

It's not your word vs them.

You just start recording them, and then if they try to stop you, their attempt to stop you is now recorded, and hopefully in the cloud where they can't delete it.