We almost had a fist-fight at the field over this!
One newbie mounted his switch with ON, up.
The expert tore him a new one over this!
I tend to mount mine with forward being ON, or inside with a pull-wire for ON.
I have had a hand-launcher turn the switch OFF when forward was OFF, and I had one turn off itself flying on the slope, with forward ON. It went thru a bush, which rubbed it OFF. Drat!
On some of my scale planes, the switch is in the cockpit, with a pull up for ON.