In the scene where Annie (being Hallie) sends Hallie (being Annie) the fax that says 911 with the dog, Martin brings it in when the Grandpa asks for more wine. Martin fills up his glass, and also fills up the mom's glass which has a little bit of wine left. (which would indicate she already drank a glass) Then later in the movie when the mom arrives at the hotel and is drunk, she walks past the real Annie thinking it's Hallie and obviously shows that she's drunk. When she leaves, Annie says: "She's drunk! Mom's never had more than one glass of wine in her life!" Well, little does Annie know, her mom just had two glasses the other night!