I don’t know if anyone else does this, but it works every time for me. There are variables though.
I’ve been using this trick to conceal small items such as packets of gum without the need of blind spots. It might only work for people who have big hands like me. You basically just have to pickup two small items at a time, putting one in your basket but keeping the other in your hand. If your hands are big enough or if the item is small enough, it will be completely concealed and you can walk out with it remaining in your hand, or just casually put your hand in your pocket and deposit it there.
Real life example: I’ll usually pickup two packets of gum from the shelf at the same time, and only put one in my basket while hiding the other in my closed fist. I’ll shop around for a bit, then pretend to get a phone call. As I put my hand in my pocket, I’ll smoothly deposit the gum in my pocket while taking the phone out, then pretend to have a conversation over the phone. This has worked 100% of the time for me, multiple times.