Someone's gonna have to explain to museum staff at large that a backpack with both straps over someone's shoulders is in considerably more control than when slung over one shoulder, "purse style". A backpack isn't shaped like a purse, and the weight doesn't sit like one. The only effect of forcing me to wear it over a single shoulder is that it swings more, slides constantly down my arm, and requires more of my attention to keep in place because of the strap design/construction. I tend not to wildly spin around when my back (or front, or side) is less than a foot from museum exhibits/other people anyway.. Also, sending me out to put my camera in the car has zero effect if you don't check up on me at all when I come back in.
There was a Jr High across the street and I couldn't get over how
If you're ever in San Jose, spend an afternoon or two with your nose pressed against the Grand Temple doors. (You don't have to, I could smell the incense from the steps. G'damn, that smelled good though.)