Yeah, I'm thinking they link up the email accounts when they see that the addresses/phone numbers/names are the same. Here's what happened to me. I've had an existing account with Disney for years. In that account, I set up FW as my favorite resort.
Once all this pin stuff started happening I set up a new email and set up a new Disney account with that email. Never chose a favorite resort. In fact, did nothing on that account except add an two itineraries - one with "needs accomodations", one with "staying offsite" (as per instructions

). So, the next day I get an email from Disney Destinations on the NEW email account saying "we're so glad you're considering FW for your upcoming vacation..."
Don't think this new email thing is tricking them.....at least not for me!