DJClayworth's comment under this question seems very valid to me:
Can I suggest not giving dates as number/number/year as they mean different things in different parts of the world. Writing the month name avoids confusion.
Do we insist on that?
(I'd say yes, and I'm writing this as a question here so that we have a meta post to point to).
Added: Suggested course of action:
We edit them out if the date is ambiguous and we know (from context) which date it should be; optionally we leave a comment (pointing to this meta post). If we cannot resolve which date it is, we leave a comment asking them to write the dates in an unambiguous format (pointing to this meta post).