Austinmom is exactly right. These shops are done every day without a hitch. I don't think you'll ever get a comment, but if you do you can say something like "Oh, yes, I picked up lunch for someone else. This one's for me."
The first shop I did was fast food, and at the time I thought the guidelines looked monumental. After a while this will all be easier, but we all have to start with that first shop.
If something doesn't go right for you, talk to the company. I can assure you from my personal experience that they understand there's a learning curve for new shoppers.
Mary Davis Nowell. Based close to Fort Worth. Shopping Interstate 20 east and west, Interstate 35 north and south.