How many days has it been? My friend who just converted to Macs bought a new 15" MBP a little more than two weeks before they announced the 2011 model.
She went in about 19 days later saying she had just gotten an Apple email announcing the new ones. She didn't need to argue or cry, she just asked about them, mentioned the email. The manager overheard the conversation, walked up to the employee and said to give her a new one.