Yeah, I wouldn't bet on it.

Most municipalities that consider a fixed drivetrain a break have specific clauses in there, as Capo quoted.
If your state doesn't have that clause, then your FG is probably required to have a separate brake.

If you get cited for riding brakeless and try to argue what you've posted here, best of luck to you. You won't be the first to try that line of logic, and you won't be the last.