The technology probably cost more than the soda.
This is a step up from the secruity tags they hide in the stuff you buy, which for some reason, they can never quite seem to get deactivated properly.
What they REALLY should do is raise the bar.
You wander up with your mug from 1982 and act like you are entitled to refills for life. The sensor realizes that you are in violation of the “this trip only” policy. But instead of not filling your mug, it promptly fills your mug with a frosty serving of…