This is not true. Floridians have no advantage over anybody else. Nobody can reserve at a park. ALL reservations have to go through RA. The exception is a few parks have a few walk-up sites. If you snag one of those, you can stay in it two weeks, then your spouse can get it for two more weeks. County parks vary county to county.
I know Pinellas county gives its residents preferential treatment for Ft. Desoto.
BTW, I detest RESERVEAMERICA. $17.50 to change or cancel a reservation six months in advance is a ripoff.