Probably stating the obvious here and I normally do check the amount before I tap my card but I didn't today and... I got home to find that a £2.80 purchase has gone through as £283!
I can't get through to the shop on the phone and can't go there today so I'm hoping they'll be helpful tomorrow.
Thinking about it I generally have to ask to see the amount (and fight the urge to apologise for doing so!) so I guess people don't always ask to see the machine.