It's important to note that these aren't isolated anonymous systems. They know who you are when you pick up the scanner and can assess choose to deny service ba

It's important to note that these aren't isolated anonymous systems. They know who you are when you pick up the scanner and can assess choose to deny service based on how much they trust you. Fail a couple of random searches and you lose service. It's still financially viable to assume a little extra theft risk here because you take a tenth of the time at checkout and use less than half the person time as regular self checkouts (which use a tenth of the time a manned checkout does). They massively increase throughout in large, busy stores.