Originally Posted by
xenole
Adding a random receipt at customer services doesn't affect your offers. It's just adding adding the points rather than the items. Tried this twice last year to get some bonus Lego cards

As for till spits, hit and miss. I've picked up one or two in the past, and they have scanned at say the self service tills. Some do, some don't.
I’ve had a random one off purchase one week, show up as an offer for bonus points the following week.