Dear Mary | 4 August 2012

Q. A friend of mine put five Coldplay tickets up for sale on Facebook. They were £80 each and I assumed they must be very good seats. I sent her the money. When they arrived I was surprised to see that they had originally been only £45 each. I made a wry comment to this effect but she expressed no guilt; she just said, ‘I rather hoped a close friend would not buy them — it is a bit of a side business for me.’