Like Michael said, it may work, but not for all intents and purposes, e.g. on-set smart slates would have already been at 30fps. Changing the BWF TC stamp afterwards then works for the BWF, but won’t change the smart slate code. Not a problem when you start at round seconds, of course, but what if you don’t?
And again, Avid can track these codes.
Old habits die hard, which is why many folk stick to 30fps TC for sound (and 25fps in the PAL world even on 24p shoots), even though it makes hardly any sense in an all-HD workflow.