I think it would depend if the local ordinances for that specific track have a max Decibel allowance for race vehicles and who you get for a Tech Inspector. The safety wire thing probably isn't going to fly because of it being a safety issue.
Do you have the pieces that broke (or at least some of the major pieces)? Even if it's Aluminum it should be able to be welded by someone with a TIG or MIG that's set up for it - I would try and find a local welder and see what they would charge to weld the bracket back together for you. Too bad it's not a Blackhawk Farms event because I would have offered for you to come by my shop and I would have welded it for you with my TIG Welder (since I'm only about 15 minutes South of Beloit down I-90).
The other option is a new bracket from a trackside vendor, if you know of a vendor who's always there call them ahead of time and see if they can have it waiting for you at the track? Or you could have a bracket delivered overnight to the track or your Hotel (if your staying at one).