Graham Cluley reports in Heinz takes the heat over saucy porn QR code that some bottles of Heinz Hot Ketchup provide more than “hot” ketchup. The QR code on the bottle leads to a porn site. (It is hard to put a “prize” in a ketchup bottle.)
Graham observes a domain registration lapsed for Heinz and the new owner wasn’t in the same line of work.
Are you presently maintaining every domain you have ever registered?
The lesson here is that URLs (as identifiers) are porn vulnerable.