Re: "Flying boxes/arrays" may be the culprit??
The weight of the PA rig is relatively small when compared to the the rest of the production. A hang of 16x V-DOSC is only about #5000 including bumpers and pick. Let's say the entire weight of the PA is 10,000lbs, maybe 16,000lbs if you're flying subs. Compared to a modern lighting and video hang carried by an 'A' list artist, that's pretty minor. A large roof system like the one in Indiana was designed to support a UDL of ~100,000lbs. Sure taking the mass of the PA out of the roof would lighten the load, but then you're looking at other means of trying to support that same system, none of which are going to be any more resilient against toppling than a properly designed and deployed truss superstructure when presented with serious wind loads.
Really what it all comes down to is ballast. One point raised earlier (I can't recall if it was on this forum or another) is why venues like the Indiana state fair grounds, where the same structure is erected on a regular basis, aren't installing permanent attachment points for the towers and guy lines in the form of concrete pads that extend down several feet into the ground and weigh several tons. This would provide the rough equivalent to a permanent structures foundation, while still keeping the main structure available for use and deployment in other situations. When the permanent anchors are not being used, they should be able to be covered so that normal use of the field or track area would not be impacted.
