That's why the close button is on the underside of the gate itself, instead of in the cargo area like other SUVs. To allow you to be out of the way, so they don't HAVE to make it too sensitive. It also keeps it out of reach of kids. I also understand that the CX9 has a sensor on each side of the jamb up by the struts to detect an object inside the closing space.
I'd guess if the GMs are sensitive enough to stop at something as minor as the presence of a hand, they will stop if anything is amiss, like a slightly misaligned latch or gate. (Could that be possible on a GM product?)