I would personally like to see a roll bar or roll cage exempt. You can argue that it's beneficial for suspension function, it stiffens a chassis, yadda yadda yadda. You can do the same for pretty much any part.
If it comes down to actual cost spent (not in budget), then you could argue that replacing an entire brake system for free isn't fair because one team doesn't have the budget the other one does.
If it comes down to competitive value, you could argue that it isn't fair that the first set of tires is free. One team can afford a really nice set of race tires, and another one can't.
At the end of the day SAFETY is the primary concern. I am more concerned than most because I am the owner of the team/shop that comes out. So I need to be concerned not only with myself, but those in the vehicle. Really we should all be concerned, as if you choose to have one of the Pro-driver's drive your car you are now putting someone else's well-being at risk. Granted the real safety concern is the drag strip and not the autocross (most of the top guys are going well over 100mph in the drag race), but things can happen. You can still get up to a good 60-70mph in the longer sections of an autocross in the more serious cars. I think most teams are a single driver and the whole self-preservation thing isn't as strong as the winning thing.
If it's exempt, more people will be inclined to do it, and do it the RIGHT way. A janky roll bar or cage done to fit in the budget can be more dangerous than nothing at all. If the entry level guys can't do it or afford it, that's fine, they are probably there to just have fun anyway. If the mid-level and upper-level guys want to be SAFE and add one in, they'll do it, with no worries about it eating into their turbo or nitrous or suspension upgrades.
If you're reallllllly worried that Team A will be faster than Team B with a cage, Team B needs a bigger turbo :)
I just don't want to see someone get hurt at an event, and then everyone look back and say - "Gee wiz, why did we argue about that so much, we could have prevented XYZ from happening". That would suck.
Safety guys, safety, safety, safety.
P.S. - I like the free tires thing, makes it fun
P.P.S. - I like the brakes and other safety stuff that is free, makes it SAFE.
-Tristan