I don't remember where I mentioned that I didn't need dummy plugs running multi Fermi cards but now I have a clarification. What I previously said was true at the time but not anymore.
I had been using console clients for my Fermi cards but when I started running some SMP clients I started to switch over to tracker. Every time I tried to run the second card from tracker I got an error the card wasn't supported. To solve this I had to install a dummy plug and reinstall the driver. I might have just been lucky running the console clients.
I don't have an answer for sneekypeet.