MIke,
I have a call into Florida Highway Safety to clarify - as I have never actually seen the BRC requirement either.
As far as insurance companies go, I guess the "YMMV" applies.
My AllState agent asked me specifically if I was going "helmet less" and when I asked him why, he told me that that was an extra bit of money, and the insurance paperwork automatically assumes you are wearing a helmet. If you are not wearing a helmet, and you are not paying the "extra" premium, with AllState, you are not covered.
Please read your fine print as required.
Cheers,
Steve