I have a feeling they will start letting you bring things on that you have purchased after passing through security and that the terminals will use special stamps on your product to prove that it was purchased in the terminal.
We almost never fly from Canada so we shop at the duty-free when crossing the border by car. I will be most effected by no juice for my preschooler. When he wants a drink, he wants it now. LOLThankfully, we had already planned to drive down in April.