Interesting, I wasn't aware of this. I thought it was something like "being 
able to shut down the transmitter side only while waiting for a WoL packet".

That will not be reliable. INF-8074 says:

6) VeeR and VeeT may be internally connected within the SFP module.

So shutting down the transmit regulator might end up putting double
load on the receive regulator, and the magic smoke getting out, if the
design does not take this into account.

       Andrew