I remember that, it was Target wasn't it and they inferred her pregnancy status because she started buying unscented deodorants and stopped buying sanitary products.

Funnily enough when I'm discussing the dangerous nature of large datasets in the hands of companies/bad actors (sometimes the one and the same...) and the "creepy" effects this is one of the examples I use, I've found that if you know a little about the person and couch the argument in a way they can personally respond to, they understand even if they don't know the first thing about technology generally.

EDIT: https://www.forbes.com/sites/kashmirhill/2012/02/16/how-targ... for anyone who hasn't seen it.