Ah, the charity donations.

Esso petrol stations routinely ask for this, and the staff member ALWAYS clicks the 'no' button before you can offer your card.

Source: Somebody who drives around the UK a lot for work.

B&Q are on the naughty list too (and the cashier also frequently clicks the 'no' button).

Interestingly I haven't seen the charity thing seen here in Germany for a while. I guess its because they all are asking if you have a customer loyalty card now (sometimes for both the chain-specific one and wider programs) and there is only so much they can ask for before the cost from lower throughput becomes significant.