you booked a ticket for an event, paying £20 to do so. Then, a couple of weeks later, and a week before the event was due to take place, the organisers of the event send out an email saying there's still some tickets left, and now, to make sure they're all taken, they're being given away for free?

I am quite annoyed, though not quite annoyed enough to book a new (free) ticket and request a refund on the previous one.