Believe it or not, by opening a gear box you can actually tell if a driver rests their hand on the gearstick. Leaving your hand on top of the stick does damage to the selectors as it forces them together, wearing them down and in some exteme cases could snap them. With it being such an easier habit to end why not give it a try and not protect your gear selector and keep both of your hands on the wheel?
For more info check out this handy article by carthrottle.com!
Referenced:
Horizons: Your RAC Magazine, Hardie Grant Media, February/ March 2017
https://www.carthrottle.com/post/this-is-why-you-shouldnt-rest-your-hand-on-the-gearstick-when-driving/
Car Throttle. (2017). This Is Why You Shouldn’t Rest Your Hand On The Gearstick When Driving. [online] Available at: https://www.carthrottle.com/post/this-is-why-you-shouldnt-rest-your-hand-on-the-gearstick-when-driving/