A couple of media outlets have today excused shoplifting on the basis that self-service checkout tills are "faulty"; see this article in the Daily Mail for example. Dressing up shoplifting as some justifiable technophobic rebellion truly is a low point in the rather low-brow publishing history of everyone's least favourite paper.
They don't really elaborate on "faulty" beyond people finding them difficult to use. Sure, sometimes they can be a little frustrating. But I use them at least once a day (I live next door to Sainsbury's) and I experience very few problems and when I do the staff are usually there within seconds to help. On occasion I've had to wait for the staff to show up but never did it cross my mind to think of walking out the door without paying. When I go through a manned checkout, an experience I avoid due to their tediously slow nature, I don't walk off in frustration with my goods when the person at the checkout goes a bit too slow for my liking!
Every single day I see people who turn up at the machine and pay no attention to what they are doing. They, inevitably, experience difficulties as they forget to put an item they've scanned down before trying to scan the next one. Today the lady next to me stormed off in a huff ("Oh for God's sake!") when the machine asked her, for the first time, to put the item she'd scan into the bagging area. She continued to clutch the magazine completely ignorant to the concept of how the machine itself worked as she attempted to use the next machine along.
My favourite example was of a middle-aged couple coming the self check-out next to me and staring, dumb-founded, as I scanned and bagged my shopping in a relaxed (as relaxed as I get) manner. When their experience did not go according to plan (they were doing things at cross purposes) they seemed to get jealous (literally the man got more upset with each successful scan I did) of my ability to continue bagging my shopping and threw their shopping down on the floor (literally) and stormed off screaming bloody murder about infernal machines. (By the way I'm not particularly nosey about other people's business it is just some people are so loud or intrusively curious, as with this couple, as to be unavoidably noticeable)
Some people just aren't cut out for self-service machines. There is no shame in that. We're all different and some people are technologically challenged. But let's not blame an inability to operate machines, or to cope with a couple of minutes wait if it does do something silly, for someone shoplifting!