As a UK citizen, it stuns me that one-in-thirty pound coins is a fake because a) i can't imagine how it's possibly worth it b) out of the thousands of pound coins i must have handled, I've never spotted a fake - they must be very good. Still, the new coin certainly looks nice!
I was cheated in the most crude way in London once - gentlemen selling African street food gave me (in my change, amongst other coins) a coin that looks and feels very much like a British pound, but is Ugandian (IIRC) and has some kind of ostrich-like bird's head on it instead of the Queen's.
Obviously it's a bit different here, as the values are roughly the same, but I can see how that would happen as an honest mistake.