Ok, let's say someone is very careful, reads the manual (we'll ignore the non-existence of this part of the manual!) and checks the forums. They don"t click OK, because they are well informed, their English is good enough that they aren't confused by the slightly ambiguous wording of the pop-up message, they've read enough forum to understand that "delete all" behaves differently from "delete one" repeated, and they don't want to remove the mutually confirmed contact from the IM/Skype server. But they don't need that person on their N900 any more in their phone contact list.

So now what should they do?

It seems there is a lack of useful solution here...