Once I got a letter from Bank Of America that they had noticed weird activity on my home equity line of credit, with a weird phone number to call to talk. No one answered that number, and I don't have an equity line.
Back when "Verified by Visa" first came out, and I first saw such a page, I called my credit card company to see what was up.
The customer service people at the card had no clue what was going on. They'd never heard of it either. They told me they'd escalate the question to a manager and call my back, but they never did.
It turns out the letter really did come from BoA.
EDIT: and once Chase sent me a letter telling me to reply by September 31. http://danweber.blogspot.com/2009/08/chase-does-it-again.htm...