Well, my question concerns even the 'specific repetition gesture sequence'.

For instance, if I'm on my couch and perform the gesture while my cat jumps on the couch arm between myself and the WiSee, what happens?

Or my cat is in the other room, but walks in front of the WiSee while I'm performing the gesture, what happens?

I think he refers to having a system that, using this approach, turns on his shower when he enters it. If this cannot distinguish humans from cats, it would turn on the shower when a cat entered it.

I think that's a bad example. The typical cat would soon learn not to enter the shower.

One of my cats has actually done this a couple of times. He walks along the ledge around the bathtub and squeezes past the shower handle, forcing it away from the wall and turning on the water. It's a problem that seems to have solved itself, because it scares the shit out of him and he gets wet.