Apple Pay launched in the UK this week and caused confusion on the London Underground. People touching in with an Apple Watch and out with an iPhone linked to the same Apple Pay account are being charged a maximum fare. This issue, which Transport for London describes as "card clash" is a result of how Apple Pay works. If your phone battery dies mid trip you'll also be charged the maximum fare!
Apple Pay could also cause problems if the device used to touch in runs out of battery during a journey. This would prevent people from being able to touch out, resulting in the maximum fare being charged. Early adopters have also complained about the speed of Apple Pay compared to Oyster or contactless. Difficulties using Touch ID to authenticate payments combined with the speed at which a payment is recognised have been causing problems for some.