In my experience doing video work for some of these type events, its possible for a music festival to negotiate riders that work for the festival an implement them properly, it might take a few more people and decent planning ahead of time.
The problem is that it requires a fair bit of documentation, coordination and processes to make it work, which some festivals do fine and I guess some just don't.
The key is that your head QA person knows who is in charge of what and has a process for holding them accountable, one such way would be to create a checklist of all the items that need to be checked, based on the riders, production requirements, regulations, expected amenities, plussing, etc.
Its also needed for each stage of the process, planning with stuff like speaker modeling, truss engineering, power load calculations, network and communication requirements, etc... on to checking the event area after load in and setup is complete and continuous checks on key items for safety and a reliable performance.
So, its certainly possible to reach an optimized state where you have a negotiated list of requirements and implement them correctly.
