If it's the latter, could not the same "logic" be applied to people on the beach? If there are no signs on the beach, then the public assumes the beach is public and uses it in that manner.
BUT
Since there are deeds recorded at the county that state particular gulf front lots own to the MHW line and everyone is now an expert on "trespassing", shouldn't the public have been aware that IF and WHEN they walked on private property, that they were trespassing? Was this the "right" thing to do?
I don't want to keep posting the same information over and over again. I've already posted (maybe on one of the other threads if not this one) information from FloridaBar.org, stating that the sandy beach property, even if privately owned, is different regarding property rights, from the upland portion of the property. So, the answer to your questions are:
no,
no,
the last question is vague since "this," is an unidentified subject. Was it right for the property owner, the security guard, Sheriff's Deputy, or people who want to lie on the beach? Too many choices.