I have the whelen strobe kit on my car and it's kick a**. I use it whenever I'm parked at a show or once in a while a parking light. as far as state law goes you cant have them on while in motion, but parked stand still theres nothing against it.
Also if I was assisting someone in an accident, i would have the strobes on so the cop can find me, F**k em if they want to give me crap about it. I'll happily argue my case in court about how my strobe lights were a warning signal to other people theres an accident and to slow down, plus as a pinpoint light for the cops to find the accident.