In the UK, if the taxman screws up, he'll give the money back at the end of the year

True here as well. However, I think Bitt's point is that how are we to know if the taxman screws up without the process we go through of delcaring our taxes every year. That's why the word automatic sets off some warning signals. At least I think that's his point. I hadn't heard about any of this this until this thread.

Edit: actually the word "automatic" isn't used anywhere, but I'm gathering that's the idea.