You can't carry a gun in a backpack? Where was he stopped at? I would have no problem with nationwide concealed carry (except for certain places for security reasons). Open carry is just a show of force and unless society has collapsed or you are in a bad part of town for some reason it isn't needed.
There was a case in MI where a bar owner used a stun gun and was cleared because the state doesn't have the right to make stun guns illegal. I'm not sure why they were found to be a problem in the first place.
Judge rules against stun gun law | Detroit Free Press | freep.com