This is all speculation but that
flat bar looks thicker than the pipe wall from the photo, and much thicker than 1/8 or 3/16. I'd suggest measuring instead it eyeing it but I suspect it's at least 1/4", if not 3/8" or more, which isn't bad for 90 pounds (3 ft of
batten). Measure the pipe diameter also - outside - but
c-clamp makes it look like 1.25" (nominal or inside diameter, near 1.6" od). One
bolt per bracket is a concern, where the front one is located it's probably into a 2x10 that is bolted to a plate girder in the
balcony rail. Often not much ferrous metal in this era of
theatre structures.
I am not saying don't draw attention to the issue, and a qualified person - a registered design professional - should review it - but for your future credibility - don't draw a
line in the sand claiming it's absolutely deficient based on this thread.
I was not far from you a few weeks ago and will keep that in mind if I make that trip again.
