Professor Morris said the footage revealed nearly all would have paid had alcohol purchases not blocked the self-scanners. So the choice was: leave without pay

Professor Morris said the footage revealed nearly all would have paid had alcohol purchases not blocked the self-scanners. So the choice was: leave without paying VS put all the groceries back on the shelf and leave empty handed, wasting an enormous amount of your own time due to the store's screw-up. Not really a fair "moral test".