There is bigger fraud in parking placards than service dogs. The toughest part, some Doctors will write a note for a placard without regard to actual need. So you have met the letter of the law for the placard, but you really don't have a need.
I long ago gave up on wondering whether a service dog is legitimate. As long as they are well behaved I don't care. The problem is, there is no licensing, or universal registration for service animals to even verify whether the animal is legit..
That Florida law is a joke. If they choose to enforce it, I see the state having to pay out settlements for violating the rights of people who somehow find some strange way to legally justify their service animal.