That Sainsbury's customer who complained when the check-out assistant refused to serve her because she was on her mobile should consider herself lucky – lucky that she isn't now having said mobile surgically removed from her shopping.

"There. I've rammed it inside your melon. That way we don't all have to listen now, do we? Oh look, the melon's vibrating. How funny. Would you like any help packing?"

Much of the country seems to be rallying to the worker's support and attacking Sainsbury's for not supporting her more. Quite right too. This is a simple case of manners and respect. The customer was rude and when she clears off to Waitrose, as she says she was going to, let's hope someone secretly replaces her phone with one of those self-checking devices. Or finds it, lifts off the screen, and fills it with overpriced granola.

The whole subject of mobile manners is a tricky one, revealing generational differences. Ask any parent of teenage children about mealtimes. How long before Apple introduces a range of iCutlery, fully wi-fi enabled with touch-screen handles?

Trouble is, a whole generation does not find it rude to constantly interrupt a real conversation for a mobile one; or to text and talk; or talk and scroll, ignoring friends. These youngsters are not morally flawed; it is just a different modus operandi. Men used to wear hats and smoke pipes. It doesn't happen any more. Times change.

These youngsters will grow up and go out in the world, some of them into politics. It's not inconceivable to imagine the Prime Minister checking his texts as he stands at the Dispatch box. "Order! Order! Incoming message!"

Of course, Sainsbury's might be missing a trick in this row. Supermarket check-outs have changed over the years – Express lanes, 9-items-or-less lanes and today's self-service check-outs. Should supermarkets now introduce Mobile lanes where being on the phone is acceptable? Of course they should – but with one key difference. The check-out staff should be allowed to use their mobiles too – and let's see how the customers like that.

Staff should be allowed to text while asking if the customer has a Nectar card. Perhaps there should be Nine-text-or-les' lanes. Or OMG tills where staff are openly rude about what you're buying.

Best of all, YOLO tills. That's where they look at your sad, humdrum fare – and add unexpected, exciting exotic items.