If you get on a cops bad side somehow there isn't much you can do. Usually a pen knife wouldn't get you busted unless you said you use it for self defense so you should say you use it to open boxes or something but it all depends on the cop.
I didn't know about the loaded mag thing so I guess thats yet another reason to get the heck out of MD. My wife and I have been planning on PA or something.
I would also not just keep a gun in a holster behind your seat. It is supposed to be out of reach and in a locking container, the trunk qualifies as a locking container. If you drive a truck you had better have a locking gun case to keep it in or get ready to be taken to jail. MD is a communist state and you should act accordingly within it's borders.
"Those who make peaceful revolution impossible will make violent revolution inevitable."
--John F. Kennedy