passenger blows my car horn without permission

Rude behavior is not usually worth writing laws so there probably isn't one in Florida. There are some anti-horn laws in other states.

Some states also have laws against distracting driving - usually you hear about this in regard to cell phone use while driving which often times there are laws specifically around cell phone and texting use. However distracting driving is whenever a driver's attention or concentration is hindered from any sort of mental distraction that causes your mind to be on something else than the road.

Things like - eating while driving, spilling hot coffee, putting on makeup, a heated or passionate discussion or argument with a passenger. or perhaps someone reaching over you to blare the horn ...

Not sure how they come after you for any of that but there are some laws around distracting driving.

I don't know what Florida law has to say, but I do know that in Denmark it is severely frowned upon. My ex was driving us somewhere, with our Danish friend in the backseat, and he honked lightly at the guy in front to get a move on. Danish friend was horrified and said you can blink your lights but only under extreme provocation, lol.

Your passenger has no idea what they're talking about and could very well have endangered everyone in the car.

You're the driver. The horn is yours. I don't have to look up the law because this has more to do with insurance than the law. But if you'd like to see a cite, here ya go:
http://www.leg.state.fl.us/statutes/index.cfm?App_mode=Display_Statute&Search_String=&URL=0300-0399/0316/Sections/0316.271.html

The scenario had nothing to do with safety. Your passenger was 100% wrong.

Guess who would be responsible if the distraction of the horn blowing caused an accident? Beyond whatever fault of the other driver, it's not your passenger. It's you.

If she wants so badly to honk the horn, then change drivers. Hell, I would have done it in the parking lot, but I'm a mean girl.

Your passenger is a foolish, selfish idiot - trying to get someone to shake a leg to get into a handicapped spot? Are they for real? - and feel free to tell her I said so.