I would say avoid flash photography altogether. Some performers disallowed any kind of photo from being taken. The last show I went to, a comedy act, the entire lineup did pose at the end of the show so the audience could get photos, but we were warned that photography would not be allowed during the show. The total prohibition of photography is probably on a show to show basis.
They discourage flash photography. Some artists do not allow video recording however i was able without hinderance to use my phone for both non flash photography and video recording when permitted. Copyrights on songs and such prevent video. New songs not released yet etc.
Does your phone have a camera? I'm guessing they don't confiscate phones on the way in the door...
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