If they can't be kept from crashing (I agree, that's a realistic assumption), maybe there's still some things that can be done, apart from keeping spectators safe:
Russian company Zvedza recently started offering 36lbs ejection seats, with a telescoping pole, pneumatic/compressed air. Minimum altitude 100 ft, has already been installed in Su 26 (I wouldn't want to be the one to test it at 100 ft though). Could be useful for the Skip Stewart types.
Specs via google translate:
https://translate.google.com/transla...ru%2Fnode%2F94
https://www.youtube.com/watch?v=Ldmh9BPRIPM
Airbubba, re
I've never run across that one before
thinking of it, usually the Special Airworthiness Certificate will contain something like "This aircraft MUST display the word “EXPERIMENTAL” in accordance with 14 CFR part 45.23(b) or either registration number must be displayed per 14 CFR part 45.22 (i.e. NX)". Most prefer NX.