In message , at 13:45:29 on Sat, 1 Dec
2012, tim..... remarked:
There ought to be more dual-purpose cards, like a Tesco Credit card
and combined Clubcard, or a Sainsburys Credit Card and combined
Nectar Card. But I suspect the shops make too much money from people
who forget to take their loyalty card with them (and don't go back
later to add the points).

I would have thought that people forgetting to take their card is
somewhat lost in all the noise of the other possible "mistakes" (both
positive and negative) that affect a supermarket's bottom line.

Every little helps.
--
Roland Perry