Nah... though... there is a funny story of when me and a girlfriend were visiting Florida in 2008 (2 years after I left) - and she got stung... she runs out of the water "You've gotta pee on my leg!" - I told her to have the lifeguard pee on her leg, since he won't get arrested for indecent exposure. He actually had a spray bottle of ammonia, which is what neutralizes the venom.
RE: Portugese Man-O-War on the beach