I think the major difference between going backstage with a convention, Magic Music Days, or as a crowd control measure, versus just wandering back there, is that the former are all controlled circumstances, expected by the company. In those, an escort of some sort is provided (or crowd control CM's), and guests probably won't see too much that they "shouldn't." Guests also won't be put into potentially dangerous situations, and, for the most part, they won't be intruding on the CM's time backstage, away from Guests.
However, if a guest just wanders backstage, all sorts of glorious possibilities pop up. There are some potentially hazardous areas backstage (crazy pargo drivers, machinery, chemicals, etc.) that the CM's expect and may have training for; however guests wouldn't be expecting any of that. There's also the "magic" quotient: seeing a half-dressed character taking a smoke break or seeing a huge dumpster full of trash just isn't "magical." Finally, backstage is an opportunity for CM's to get away from the hectic onstage areas for a while. As a CM, you expect conventions, Magic Music Days, tours, crowd control, etc and you know that you don't have to take any action when you see them. But, when you see a random person walking around backstage, it is your responsibility to approach the person, ask why they're there, and escort them back onstage. Not my idea of a fun way to spend a break.
I realize that this has gone way beyond the original topic, and even beyond the posting of backstage pictures. However, in summary, if you aren't backstage because you were sent there by a representative of the company, please don't be back there. And please don't take pictures
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