Which you can do, as the inputs (and thus the required S2 component) are stored in the block tree. The S2 component can only be provided by the valid receiver of those EMU's, so you can be sure that the input & outputs in question are legitimate and can be spent, without ever divulging the address.
All you need to know is that whoever is sending them, is allowed to, which this protocol can achieve. You need to know nothing about sender and receiver.
If I catched the idea correctly, every address (in Bitcoin sense of word) is covered by an alias unique for each transaction. Were addresses used once and only once, there is no edge over Bitcoin system. But for reusable addresses such aliasing reduces the load on private ECDSA key and provides some protection from bad entropy sources (google "Debian SSL fiasko").
UPD. Probably I was wrong comparing eMunie with vexel, but let's wait for whitepapers.