QUESTION: I was once told that the notched tine in the salad fork was to pierce a cherry tomato so that it did not explode when you put it in your mouth. is this correct?
ANSWER: In the late 19th century, refrigerated railroad cars made salad vegetables more abundant, and available for most of the year. The salad fork originally featured curved claw-shaped tines and was known as a 'lettuce fork.' To provide leverage when cutting thick veins of lettuce or broad vegetables served in salad, the salad fork is made with an extrawide left tine that is sometimes grooved. This is the 'notched tine' that you refer to in your email. It was not developed to prevent cherry tomatoes from exploding.
(For additional strength, the second and third tines of the salad fork are also occasionally connected by a rod.)
Some facts are from 'The Art of the Table'