There are so many threads where the OP never returns yet, especially if it's a contentious button pressing topic, good hearted (or less cynical) site users continue, often for pages, trying to posting (generally) helpful responses - I'm inclined to think the OP was not genuine on the first instance. Sometimes they don't return after getting their a?? handed to them on a plate in which case it's still probably a good idea to lock the thread. I'm suggesting lock the thread if the OP doesn't return after a full page of replies to save people from wasting time that could be better spent helping people on other threads.