It is very different from Sam's Club, if you use their Scan & Go, the receipt checker scans a few random items from your cart to ensure they match whats on your order and they also count the total number of items. One time, there was an error in my favor where I had scanned something I put back and forgot to remove it. Another time, it was the other way around and I missed scanning and item (this is what happens when your kids throw stuff in the cart) lol.
Sam's doesn't do this if you checked out with a cashier, it is only when you use Scan & Go. I understand Costco's receipt checkers are there to help out the customer - but would you trade more checking at the receipt end for the convenience / time savings of not having to wait in line to checkout?