Continuity mistake: At the very end, on the morning after Noah and Allie had died, the way the two hold each other's hands are different between shots. Note Noah's pinkie.
Continuity mistake: When Noah and Allie are passionately kissing in his car outside of her family home, she is wearing red nail polish. She has to leave, and runs up the steps to the door, where her father startles her. She is no longer wearing any nail polish.
Continuity mistake: Young Allie goes to meet Noah at his place the night they first visit the Windsor Plantation. The two kiss outside on the porch. The two move closer to the green shutter in the close-up shot.
Continuity mistake: When Allie's mother brings her back to the house after their drive, Allie's engagement ring is not on her finger. In the next shot when she is talking to Noah, her ring is on.
Factual error: When Allie goes back to see Noah and he asks her if she's hungry, he "catches" dinner. He picks up a crab net with about a half dozen blue crabs in it. Anyone who has ever crabbed, knows you have to pick the net up fast and keep pressure on the crabs or they will exit the net on the way up. Noah picks up the net so slow, there is no way he'd have caught any crabs in it. It is obviously filled with staged crabs.
Continuity mistake: During the rainfall, when Noah says he wrote 365 letters, Allie's hair swaps from messy to brushed between angles.
Answer: She doesn't remember being married. Using her married name would only serve to confuse and upset her.