Testing the "Just Walk Out" Amazon stadium mini-mart

How it works: Customers enter the store through a special gate using a debit or credit card. A limited number of items are available — prepared pizza slices, beer, pop and a wall of chips and popcorn.

• Cameras track customer movement, and sensors on shelves determine which items have been picked up.
• After selecting items, customers "just walk out," and their payment method is charged.

💭 Sam's thought bubble: I ventured to Cincinnati with my wife and neighbors for the Hell is Real Derby this weekend and tried out the tech for myself.

• The theoretical efficiencies gained by avoiding lines are outweighed by the discomfort of being tracked with extreme precision and the unpleasantness of not knowing what anything costs.
• You can sign up to receive an itemized receipt at a kiosk near the exit, but that seemed to defeat the purpose of expediency.

By the numbers: My charge from Saturday is still pending, but my credit card statement shows a $33 purchase for a single Tecate tall boy and two Diet Pepsis.

• Even by stadium pricing standards, that's unconscionable.