most are automatic and they do not have a flash on and off but I suppose you could put something over the flash but then if it did happen to take a picture at night you wouldnt be able to see what it was that set it off.
while leo probably wouldnt be around at night and if they are you can assume that they have already found the grow here they usually search for it using helicopters during the day only, they do maintain there cameras if your unlucky enough to have them set up cameras instead of just destroying the plants.