I disabled the one keymapper app I use (KeyRemap4MacBook) and tried again. Same thing. If I have DoubleTap Cmd as my combo that loads Alfred, then Cmd-\ will always load it too, every time. And I use an Apple keyboard. And I have no WorkFlow hotkeys setup yet.
So I'm not using DoubleTap Cmd to load Alfred. I reverted back to the default, Alt-Space.