The swipe transaction system doesn't provide a mechanism to authorize a transaction for a specific amount, unlike the chip system. That is - you swipe, and the

The swipe transaction system doesn't provide a mechanism to authorize a transaction for a specific amount, unlike the chip system. That is - you swipe, and the merchant uses the details on the magstripe to make some arbitrary transaction later on - potentially weeks or months later as I've found out in the very few places in the UK that still run offline transaction systems. With a chip system, you authorize a specific amount and no more within a dedicated machine, and the merchant doesn't get a hold of all the details necessary to make another transaction.