About 3 years ago, Hoover offered 2 free flights in return for spending £100 on one of their products. They had no idea how many people would take up the offer, and it ended up costing them £48m.
2 years ago, the Daily Express offered a cruise for £10. Again, it was massively oversubscribed, and many people were disappointed.
View the report on BBC’s Working Lunch programme
And last year Threshers’ email discount backfired on them.
Remember, if something seems too good to be true, it probably is.