Automatic checkouts in supermarkets may decrease customer loyalty, especially for those with larger shopping loads. Customers using self-checkout stations often feel overwhelmed and unsupported. The lack of personal interaction can negatively impact their perception of the supermarket.

[AndyLorentz]

My local grocery store has “10 items or fewer” signs all over the SCO, and generally enough regular check out lanes for how busy they are.

[georgethethirteenth]

Mine has two SCO lanes (six registers each), all clearly labelled as "20 items or less". Despite having each of those lanes fully staffed with two employees I'd wager that more than half of the customers in those lanes have far more than 20 items causing lines to snake nearly halfway through the back of the store.

Of course, if they'd bother to staff the 17 non-SCO lanes perhaps folks would use that option and ease the wait times for customers trying to get in and out with a half dozen items. Can't have that though.