This issue has come up a few times, and I take a slightly different view of it. I want people to understand what the immunity in Fla. Stat. 776.032 actually provides.
Fla. Stat. 776.032 (quoted in relevant part)
(3) The court shall award reasonable attorney's fees, court costs, compensation for loss of income, and all expenses incurred by the defendant in defense of any civil action brought by a plaintiff if the court finds that the defendant is immune from prosecution as provided in subsection (1).
I agree that the statute says "IMMUNE" from civil action, but it's going to apply AFTER the suit is filed. There's no magic immunity filter at the courthouse to block these cases from being filed. You will incur expenses to defend against the suit. Unless your insurer is picking up the tab, you likely will not recover any of these costs despite what the statute says.
Take the seemingly clear-cut example of waking up at 3 AM to the sounds of someone in your home. You walk into your dimly lit living room and realize there's someone there who shouldn't be. You say "freeze." He doesn't, maybe even makes a hostile movement in your direction. You shoot. You turn on the lights to find you've shot a 15 year old who was probably there to lift you're PS3, big screen TV or Wii. He may have been carrying this item in his hands when you shot him. He may have been hopped up on drugs. He may have been armed himself at the time. Whatever. Still, the kid's parents will find a lawyer to take the case.
Two months later someone serves you with papers. You're being sued. What about IMMUNITY, you ask? Guess what? You (probably through an attorney) will file a response in court denying liability and requesting a hearing on the issue of immunity. Most likely, the judge will hold a hearing, will listen to evidence from both sides, and decide whether you're immune and the case can be dismissed without a trial.
Depending on the level of ambiguity in the facts - e.g., the teen's parents claim he was drunk and wandered into the wrong house, the teen survives and says he was sneaking in to visit your daughter, whatever - it's conceivable that it could go all the way to a jury trial and the jury will determine whether you were lawfully exercising your self-defense rights. (If I ever get sued for exercising my right to self-defense, I'm hiring an attorney. It's expensive, but not as costly as screwing something up and losing what should've been a slam dunk case.)
Let's assume the judge decides you're immune. Now you're entitled to recover your costs of defense from - guess who? - the same scumbag who broke into your home. (No, not the lawyer who filed the suit on the scumbag's behalf and not the court.) What are the odds any intruder you shoot at 3 AM is going to have enough $$$ to pay your attorney fees? If he had that kind of coin, he wouldn't be breaking in to steal yours. So the judge will "award" you the costs you paid to defend the suit, and all you'll have to show for it is a nice piece of paper signed by the judge saying the scumbag you shot now owes you money.
Why will an attorney take this case on behalf of an intruder, knowing that immunity will likely bar the suit and that the attorney won't make anything if it does? Because if you've got insurance, there's a chance your insurer will pay out a few grand to keep from paying $5,000 to $15,000 to take it to court. If your insurer doesn't offer a few grand upfront, but decides to take it to the judge for an early ruling on the immunity issue, there's an additional slim chance the judge decides a jury needs to make a finding of facts on the self-defense issues. If that happens, your insurer is likely to increase its offer to the intruder/plaintiff just to avoid paying another $10,000 or so in legal fees.
That's our legal system (and explains a great deal about why I decided to stop practicing law.)