I have read every post from this thread. Very interesting, I must say. Here's the bottom line. Those wardens had no idea what your intentions were with loose shells laying around in your truck, regardless of how (or why) they got there. As previously mentioned, YOU WILL NOT BEAT THEM!!
Why they stopped you like that is strange, but you must have stuck out to them for some reason. I'm not placing blame on you and your friends, but they are the law and you're a non resident alien in Canada. Those Canadians ain't no joke!!