After watching the video, it appears to me that the man was under the age of 21. If you notice, she was the only one handing the box of wine, and she made a funny gesture turning around (to see if anyone was watching perhaps?), before taking the box off of the shelf. I would think, being a man, he would be pretty likely to carry the box out of the store for her if he was of legal age. I would speculate that she was not purchasing the wine for just the young man necessarily, simply because most younger adults would more likely be wanting beer or a bottle of whiskey to mix if it is just for them alone. Just my perspective.