Why is off-tracking a particular concern when making a right turn at a narrow intersection?

Correct answer to question 124 (Combination Vehicles): The trailer's wheels can cut the corner and go up onto a curb or into another lane if not accounted for

Why

Because the trailer's wheels track inside the tractor's path, a tight right turn at a narrow intersection can cause the trailer wheels to climb a curb or drift into an adjacent lane if the driver does not swing wide enough first.