So I refused and made it clear I would walk away. The sales guy went though the whole ‘it’s not a problem, I’ve bought cars from here and haven’t got spammed’. In the end he had to get a manager and it turned out that the option could be removed from the contract, three menus down in the system.

Sounds like no one had ever asked before. I imagine GDPR will have changed this to opt-in.

I scratched that, and other lines, out of my rental agreement when I rented my New York apartment. The landlord agreed.

I don't believe it'll be feasible to purchase just one person's purchase data [easily], but if you knew who you wanted to get to, it should be possible to narrow the targeting to get to them

[1] http://www.oracle.com/us/solutions/cloud/data-directory-2810... [ctrl+F + mastercard]

but i guess it might be different for different acquirers.

the purpose of loyalty cards is that the messages are usually acquired or processed on non-bank systems so they can go into much greater detail and include individual sale item details

With the advent of the chip and pin cards in the USA, it seems logical that just about everyone upgraded to equipment that does support it; which might explain why you are only seeing this in the past year.

(quizzical look)

Are you aware of their MPerks program? Tied to your phone number and an email address, electronic receipts, tracking of your savings, online/in-app clipping of coupons auto-applied at checkout time, automatic "rewards" of $2-3 for every $150 you spend.

The only part of a traditional loyalty card program it doesn't have is making their sale prices apply only with card, but it definitely gives you measurable (and measured) discounts both passively through those "rewards" and actively via the in-app coupons.