“Buy two, get one free, says your supermarket’s promotional folder. Great news! There’s a promotion on your favourite wine and it starts tomorrow. The following day you head straight for the shop in your lunch break, only to find that the shelves are already empty. Oh well, they must have miscalculated the stock. I bet that feels familiar”, says Shari De Baets with a grin. She is a doctoral research associate who recently obtained her PhD based on research that could help prevent such situations.