He was detained without probable cause, reasonable suspicion, or even mere suspicion that a crime had been, was being, or was about to be committed.
Or do you think that when a cop demands you relinquish your firearm that you can reasonably assume that it's a consensual encounter? I don't.
See Florida v. J.L.
You can think what you want, but if you're a lawyer for "Jeremy", you're the only one going to collect on this one........and Jeremy ends up the loser.