They've been doing it for years round our way, in all the supermarkets and similar. Even ASDA I think - which would be bloody cheek in their case. "Minions" would be better.

I agree with DMG that John Lewis is different - and it pays off. The people working there are always incredibly friendly and helpful, in my experience. (The supermarket Waitrose is owned by John Lewis. I think they have the same partnership system. But I don't know what they call them on the PA.)