Why can't it be opt-in instead of opt-out? Or can we have more granular control overall? On an application, module, class, function, and block level? That way my super tight hit loop that I can prove does not overflow gets a 2x speed up, while the rest of the code is safe. Oh and I can always recompile it to be always safe and analyze crashes in the real world, no t just my silly unit tests that amount to 2 + 2 == 4.