I obviously know that. But if you do something that angers (okay, annoys) a customer, it's not good business sense. How likely is it someone will shop again so soon? Why the ridiculously short expiry date?
Perhaps it works by getting someone to finally take the plunge and buy that new TV or games console, or maybe they bank on there being a low chance of it being used but I will remember being given such a voucher and think good things of Sainsbury's even though I actually didn't benefit at all.
Perhaps Sainsbury's needs to update my account to have 'old cynic' flagged so I stop getting them, when others will think they're being really well treated!
I am forever being offered vouchers for £x off my first on-line shop - from Tesco and Sainsbury.
Similarly £3 off my next shop over £30. Firstly, I would find it difficult to actually spend £30 in a single shop (unless I buy several bottles of wine), secondly, if I did manage it, I would not be able to carry it all home. I'm not sure how the system works but, having failed to use my £3 off £30 vouchers, I now get £2 off £20 instead, which I can use. I do have a houseful of socks as a result though
I rarely buy household goods from the main supermarkets - high street discounters are significantly cheaper - my usual shampoo, on 2 for 1 offer at Tesco, just about matched my usual high street discounter.
Tuna - 4 tins: Tesco £6, sometimes on offer for £4. Always £3.69 in B & M!
Q) Why do Tesco maintain this higher price?
A) Because people believe the line 'always cheaper' and assume it is a good price being offered by Tesco because they are such jolly decent chaps!
PS no malice to Tesco, they are all much the same, it's just that I use Tesco more than the others - but only when I have price checked first!