When I was pregnant my FIL "helpfully" took it upon himself to check out the cost of life insurance for DH and I. He did so on various comparison websites, and didn't just check - he actively registered, using my email address.
I have 3 email addresses. One for work, one for personal (family and friends) and one for bills, online shopping, and this sort of thing. I'm inundated with spam in the last address, and had never had spam to the personal one, ever - it's my full name, no dots, at a yahoo address. I've had it for a decade now, so it's my main address, really.
I just deleted 13 spam messages from my personal account in under half a day. I'm going to have to set up a new account, create an address book with 200 people in it, check the old one regularly as I'll be on some group mails where the sender will forget the change... such a bloody hassle. And all because FIL decided to register me without asking.
The insurance info was worthless anyway, as he didn't factor in that DG has a medical history, as do I, so none of the prices he found were remotely relevant. hmm And the best bit? FIL works in IT. How can he not know that this is a complete nono?