They will most certainly be tracking a lot more than just you picking up your item. The data they collect about shopping behavior will be interesting. Like, how long I hesitated before I picked up something, what I had already in my "cart" at the time, what deals I looked at but passed on, etc.
If you take a slice of cake, hold it for 12 second, frown, put it back, spin clockwise three times and buy a lowfat plain yogurt, you will get a discount for sugar-free pastry on your next visit... if you did it just right.