Plaidophile

So, while Apple only explicitly mentions four-finger gestures, there's actually at least one five-finger gesture — doing a four-finger gesture while dragging with the button clicked. I had been doing this automatically without thinking about it (since four-finger gestures are the easiest way to do Exposé-to-desktop with the new keyboard, and the only way to do it one-handed) and only after doing that a few times did I realize, wait, there's still no physical button!

Okay, granted, the gesture only involves four fingers, but it's at least smart enough to know that the fifth finger should be ignored for gestural purposes since it's what's holding the touchpad surface down.