Bayou brother, the simple fact is that a lawyer who wants to pork you will hang his hat wherever he can. I've seen them argue that night sights and lasers made you some sort of ninja assassin of the darkness. They bring it up, we shoot it down. (Pun intended.) With a solid defense, that's no problem.
Yes, it can be useful. That's why cops are going to gun-mounted lights in duty holsters in droves. You'll be facing the same bad guys as the cops, and with backup farther away.
Key thing is to remember that it's not a flashlight anymore: it's a gun with an added device for aiming, last-instant target confirmation, and blinding the opponent in the instant you have to shoot him to help keep him from carrying out what you're shooting him FOR. ALWAYS have a good, powerful pocket flashlight with you for routine tasks and tactical search.
We have to keep answers short here in GATE, but you can find my article on this in my regular column in the current issue of GUNS magazine, on newsstands now or readable at no charge at www.gunsmagazine.com