I came across this paper towel dispenser in the restroom of a local church, and just had to snap a photo with my ever-present fuzzy-little-camera-phone.
The instructions say to push the button, then pull the lever twice. Following these directions dispenses a certain amount of paper towel. At this point, you cannot pull the lever any more (unless you push the button again). I suppose the objective is to limit the amount of paper any given person uses. But all one need do is push the button again and then dispense two more lever-pulls worth of paper. And push the button again... and again...
I suppose the idea is to prevent people from wasting paper, by forcing them to take an extra step and (hopefully) think about what they're doing. But I suspect the press-pull-pull-press-pull-pull process could be just as mindless as the pull-pull-pull-pull approach.
If we want people to not use too much paper, why not just put up a sticker saying "Please don't use too much paper?"