Question 2 - Why does the Waitrose self-scanning service require me to register at every store separately?

The question was slightly truncated above - let no one accuse me of censorship so here it is in full:

Why does the Waitrose self-scanning service require me to register at every store separately when I want to use their hand-held scanner thing? It's really frustrating...

Waitrose, along with John Lewis, pride themselves on their high level of customer service. When using self-scanning, there is no need for any interaction whatsoever with any member of the staff. (I use the phrase 'member of the staff' when I should, of course say 'partner' since everyone will be a joint owner of the business, hence the caring about the well-being of the company. Beat that, private enterprise fans!)

Clearly the lack of opportunity for the partners to show their appreciation of the customer is a bad thing and so, at least once in each branch, self-scanning customers must avail themselves of the charm, helpfulness and high efficiency of the people who work there.

(Shame on you if you read ANY sarcasm whatsoever into the above. The tone is warm and affectionate.)

You'll note that, even including re-registering for the service, it's still dramatically faster than shopping the old-fashioned way.

Alternative answer - the customer data might be held locally at each branch to speed up the process since the vast majority of customers probably use the same branch every time. (This is a guess and does not come from any inside knowledge. If it turns out to be true, that cannot be construed as revealing of a trade secret since it has come from my imagination, perception and guesswork.)