I think that if a thread intends to be useful for future users...
E.g. where is a good hairdresser? Or...
Where is good to live in HK?
Irrelevant posts should be deleted as necessary.
BUT...
When threads are supposed to spark a debate
E.g. "should the queen get a multipack of Crisps for her birthday?"
Change of subject should be welcomed unless it is objectively offensive.. especially when op is involved.
Mat, you must just get offended quite easily. I've never reported one of your posts even though you've insulted me now and then