I've been riding motorcycles for almost as long as I've been riding bicycles, and I've never pushed down on the pedal thinking it was my rear brake in a panic situation.............

At one point between three motorbikes I had one British right side shift 1-down, 3-up. One British right side shift 1-up, 4 down. And one Continental left side shift 1-down, 5 up. I rode all of them every few days and never had a problem keeping it all straight.

I'd keep my bicycle "continental" style, if just for the cable routing (assuming Campy calipers).