Well are the parents being honest LOL I have a freind who told me her 3 yr old knew the letters but what she meant was he knew how to sing the alphabet but he could not identity them.
I have a lot of friends with kids and there is only 1 of them who has a girl who really did know the letters at 2 like my DS7 did. She is 3 now. MY other DS3 is no way near ready to learn the letters and numbers.

Unless you see it for yourself I would not believe just believe it all.