> I read somewhere (can’t remember the book name unfortunately) that Tesco in the UK faced this problem when they started sending out personalised coupon booklets based on loyalty card purchases. People were freaking out. Then they started adding coupons to the booklet designed to be irrelevant - say if they figured out that someone was newly pregnant, they’d send a few pages of baby stuff, but also inject lawn mower coupons and stuff only men would care about. That achieved the whole targetted effect and avoided looking creepy for just a few pennies more.

It was Target in the US:

https://www.nytimes.com/2012/02/19/magazine/shopping-habits....

> As Pole’s computers crawled through the data, he was able to identify about 25 products that, when analyzed together, allowed him to assign each shopper a “pregnancy prediction” score. More important, he could also estimate her due date to within a small window, so Target could send coupons timed to very specific stages of her pregnancy.

> ...

> “With the pregnancy products, though, we learned that some women react badly,” the executive said. “Then we started mixing in all these ads for things we knew pregnant women would never buy, so the baby ads looked random. We’d put an ad for a lawn mower next to diapers. We’d put a coupon for wineglasses next to infant clothes. That way, it looked like all the products were chosen by chance.

I remember during college I was working at Tesco, and a customer way buying a lot of baby food, and she had received some Clubcard coupons for them. I asked her if she had grandchildren, she said no, but her husband really likes baby food.

A niche yet to be exploited?

You still get that if you shop online, everything you ever bought suggested as an add on to your basket.

I can see how this could cause embarrassment and, maybe, awkward questions if one's partner also uses the same account.