IMHO that's a grey area these days. Years ago, in AH2, I would probably have answered: "Yes"
But there are so many players who just park their tank near a town, base or a factory to make them flash and go away, sometimes for hours. The problem is: In AH3, you often have no chance to find them at all, because they are hiding in those dense woods or even in some building.
So I made a personal decision: I don't use film in battle/combat situations. They're fighting for the town, we just got a white flag and there's a m3 somewhere? I better watch the maproom, film is off limits. Same when a GV is in town and just stopped smashing the buildings because he spotted my Ju-87.
But if I notice a base flashing for an hour without anything happening, I might take a look at the film if the terrain is particularly nasty. In the past, I sometimes even called out my intention on CH200.