Most lawyers familiar with local government law know the Triannon Park rule on government liability - the government isn't liable for protecting you in its enforcement of rules, even rules for public safety. Triannon Park involved a case where a property owner tried to sue a local government for being negligent in inspecting a building during construction when it turned out that the construction was faulty.
In DEP vs. Hardy, here's the opinion, the 5th distorted the Triannon Park decision beyond all reason to overturn a jury verdict for $1.5 million against the Department based on negligent failure to supervise (and trespass). The court held that the Department did not have any duty to prevent one of its enforcement officers from applying an unadopted (and therefore illegal and unauthorized) 200 foot wetland buffer requirement against the landowner, even though the agency knew, because of another case, that the guy had a practice of applying the rule and that it was unauthorized! Yes, that's right folks, according to the 5th DCA, the government has no liability when it allows ita employess to make up rules, enforce them against you and drive you out of business, which is what happened to the property owner here when it couldn't satisfy the Department regarding how it would address an illegal fill violation because the equally illegal buffer rule was applied.
Today, of course, the landowner might have recovered at least legal fees by fighting this in an APA hearing. But this holding extends sovereign immunity and tort defenses to agencies that basically let their employees run wild and abuse the public. So the agency can drive you out of business, but at least you may win your administrative case eventually and your attorney will at least get paid.
But that's not ALL the damage the court did. It also distorted trespass law in the process, at least for businesses. The jury had found that the agency employee trespassed when "inspecting" the property without a warrant. The court held that because a business (chipping trees) was run on the property, it was open to the public and there was no trespass. SO, the 5th has taken the position that any property owner that runs a business on part of a property opens the entire property to the public. Think about it - a junkyard with an office open to the public opens its entire operation to the public. A farm with a farm store - same thing. Basically, under this opinion, anyone who runs a business must post any areas of their property that they don't want the public to enter.
That's not what I remember from torts - I believe that the traditional rule was that the invitation to enter property applied only to those areas to which a reasonable person would expect the invitation to extend. In other words, running an office might invite people to enter the office, parking lots, etc., to transact business, but not to the other areas of the property.
Of course, maybe the 5th is just destroying the constitutional obligation of agencies to obtain a warrant before searching premises. Isn't it nice that our agencies have so much respect for the rule of law, and that our courts ensure that only laws and rules that are properly adopted are enforced against us.