I haven't gotten around to reading the Bitcoin paper yet. But in cases where features like this are added, don't they rely on most miners moving over? Otherwise, won't some miners reject the new block while others accept it?
Or it is only for non-confirmation mode that "dust" is dropped?
If you're thinking this would result in a block chain split I don't think that's the case. This affects which transactions get relayed and eventually included into the blocks miners are mining against, but it doesn't mean that blocks with these transactions would be rejected by any client.
Or it is only for non-confirmation mode that "dust" is dropped?