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.
And last year Threshers’ email discount backfired on them.
Remember, if something seems too good to be true, it probably is.