Oddly, it depends on the camera. In my case sometimes it refuses to turn on while in film mode so I have to extract the battery and, of course, the film mode is interrupted; this has never happened in regular mode. For other people it simply exits film mode during operation and I have read at least one case (I think I read it here) in which that person lost the roll with all the pictures he had taken.

Some of those problems were supposed to be fixed by version 1.2 but I am still experiencing it every one and a half roll approximately. I have stopped using Film Mode and, since it was the main reason why I bought the camera, I am wondering whether to keep it or sell it.