Evan Schuman's StorefrontBacktalk

The U.K.’s second-largest grocer is experimenting with checkout lanes that can quickly be switched from cashier-staffed to self-service. The 520-store Asda chain, which is owned by Walmart, is expanding a one-store trial of the quick-switch lanes to four stores and reporting that a “surprisingly high” percentage of customers are choosing to use the new lanes.

At first glance, this looks likely only to expand the problems self-checkout already generates: theft, slowdowns when associates have to verify age for alcohol or tobacco, and equipment that’s simply frustrating to customers. But opening up all unstaffed lanes as self-checkouts might actually make self-checkout work better.

The chain’s hope is that the hybrid lanes will make it possible to have all lanes open all the time—just not necessarily staffed. In a typical Asda superstore that has more than 30 lanes installed, the number staffed with a cashier may be a dozen or less. Turning all lanes into hybrids would dramatically increase the number of self-checkout spots, without losing the ability to open a staffed lane at any time.

“So far it’s proving effective in reducing queues and improving service levels during extra-busy times in the store,” an Asda spokeswoman told U.K. trade magazine The Grocer. “The concept is to provide customers with a checkout that is always available.”

But there are interesting differences between a conventional self-checkout setup and these hybrid lanes. For one, all the things customers miss with a self-checkout area (with the obvious exception of the human cashier) can return. Racks of impulse items? Check. Room for a full-size cart? Check. Slightly easier control of children? Check. No limit on the number of items it’s practical to check out with? Check.

In fact, for some customers a hybrid lane that’s serving as a self-checkout may be the best of both worlds. With enough hybrid lanes open, a customer could afford to take her time, change her mind or leave briefly to collect another item. Juggling checkout and kids becomes slightly easier when there’s no impatient line backed up—with enough lanes open, waiting customers can switch easily.

And some customers will be happier without as many prying eyes around when they’re making purchases where they’d prefer a little privacy. That privacy will have to be an illusion, of course—the classic self-checkout problem of customers neglecting to scan some items isn’t going to go away. And for the hybrid lanes, cameras will have to fill in for an associate hovering around the self-checkout area.

Unfortunately, cameras can’t replace the other functions of that self-checkout associate, like age verification and dealing with pricing discrepancies.