True story: ages ago, I was looking at buying a MTB from a guy, and we went out for a ride, switching bikes. He had the brake switched because he rode dirt bikes, and thought it would be safer.
He crashes on my bike twice. Once badly. I had a few close calls.
So, in order to solve a problem that does not even exist, he made a mod to his bicycle that makes any other bike he rides (borrowed, rented, demoed) more dangerous for him.