Another factor with the early planes is the rudder/brake peddles. As you push the left rudder peddle the brake on the right side comes toward the pilot making it possible to be pressing the right brake without wanting to. This works the opposite way also.

I've had this happen as well. The only solution is to recognize this right away, center the rudder and apply both brakes to stop the aircraft. Yes, very scary. Especially when you're looking at the trees on a narrow grass strip.