On Saturday and Sunday the hide operates solely on the keypad system, as the rangers don't come to open or lock up, I believe, so there is nothing really to stop anyone sitting in as long as they like. Monday to Friday (or maybe Thursday) it's a different story with the ranger unlocking/locking the door around about the stated times.
Since the rangers took over the running of it, it just isn't the same place (feeders going unfilled, variety of food for birds appears to be down to just peanuts when they are re-filled, vegetation in front of the hide having to be trimmed back by visitors to be able to see the area directly in front etc). And if, as I suspect, the ranger in question is the one I think it may be, he doesn't appear particularly interested in what birds/wildlife are around either, being more concerned about locking up than whether there is anything of note around.
My experience of Fife Countryside Ranger Service compared to the Dundee Countryside Ranger Service is night and day with the Dundee ones full of enthusiasm for the countryside/wildlife and Fife's full of enthusiasm for getting home for his tea (there was a young ranger a while back who was enthusiastic and interested but he seemed to disappear as quickly as he arrived).