Factual error: If you have ever actually seen London then you can see that the route Hallie takes to get to the house would take you all around London.
Factual error: Placing Hallie and Annie alone in an isolation cabin without a counselor sleeping there to supervise is an enormous liability. No camp that cared about its reputation and about avoiding a lawsuit would ever put two girls in such a potentially unsafe situation.
Factual error: Copyright stamp at the end of credits reads MCMMXCVIII, that is the third M is superfluous.
Factual error: Hallie, in London, dials the operator and says she wants to place a collect call to Napa, California. The phone rings once and Annie answers, then begins talking. On such a call, the operator should have told the recipient, "You have a collect call. Will you accept the charges?"
Factual error: At the hotel, Chessy's door to her room stays open after she goes into the other room to discuss the whole 'dad doesn't know' matter. In real hotels, the guest-room doors have auto-closing mechanisms for fire safety and security. The door would have swung closed and locked Chessy out, but even though this is a 4 or 5 star hotel which would be fully equipped as far as modernity's, it doesn't.
Factual error: After Hallie and Annie send Meredith out on the air mattress onto the lake, Meredith wakes up and there is a bird on her chest. The bird is a Red-Crested Turaco, which are native to Africa.
Factual error: In the scene in which Annie and Hallie are fencing, it portrays it as though Annie does not win until she hits Hallie (effectively knocking her into the water). However, in a real fencing match, Annie would have won within a few seconds after they started. Once a person is backed off their end of the strip, their opponent automatically gets a point.
Answer: I think she was scared of falling in love with Nick again, and maybe because she thought they were better off not together, considering they became successful and achieved each other's dreams when they were apart.