During the last year and a half I've seen dredgers, cranes and heavy equipment restoring the beach and dunes in front of The Retreat. According to the US Supreme Ct decision upholding Florida in its case with the Destin homeowners suing over the restoration here:
http://www.supremecourt.gov/opinions/09pdf/08-1151.pdf
It seems that if the county, state or federal govt funded any of that restoration that I saw take place recently then they absolutely have no right running beach goers away with security force - if they ever did have that right in the first place. In addition I would argue that the storm that eroded that part of the beach a year and a half ago significantly raised the high water mark that once prevailed thus creating a significant amount of dry sand "public" in it's current state. In addition, their HUGE "Private Beach" sign has been erected on public sand right off of the public access and should be removed immediately. Certainly there is an ordinance preventing people from putting major signage on the beach? It may as well be a billboard it's so large and it's the only sign of its kind I've seen on the beautiful beaches around here! I'll gladly call someone to remove it if pointed in the right direction - I just moved here full time so I don't know the govt entities yet. But I can tell you I'm hot about this and don't intend on dropping it!
Not weighing in on the use of the beach, but there has not been any work at the retreat that was county,state or federally funded. There is a project being developed for 30-A beaches, but it is still being developed. That project will include the retreat area.