You do realise the pyro you are talking about are basically giant sparklers, right? No flames. The foam was not fire retardant, but should have been. Whose to say he Great White camp were told it was?

You also have a misconception if you think band members inspect venues or clubs. In most clubs they even stay in their tour bus until show time. If the first time they see the place is when they hit the stage, and let's be honest under stage lights you can't see much, how would they be able tos scope the place out for safety issues? Again, this is and was the manager's and operators job.