They are going to have more trouble turning right to park than they will turning left. Since they will tend to pull further forward and cut sharper when going left since they can better see where they are in relation to the parking spot. When turning right, they have to use more judgement looking "across" their car to see where they should start their turn, and they will tend to start their turn sooner, cutting the corner and turning less sharply, if that makes any sense.