A man was walking around my shop with his mobile phone in his hand, looking at the prices of complete dog foods. Strange, I thought, because there is no mobile signal in the shop. In fact, no signal outside for at least 200 yards. Peering over his shoulder – as one does – I noticed he was on Amazon, comparing prices with what we had on the shelf. So I quietly turned off my WiFi, killing his connection. That stopped the cheeky beggar using my Internet connection to check out Amazon prices. The funny thing was he had no idea what had happened.