Yes, this does indeed happen. If Disney knows you are going annually, bi-annually, etc, there is no need on their part to try to lure you.
We go at least once a year. Other than 2002 (our first visit), we have had a discount code for every vacation. My last vacation was Dec 2009 and the discount I received on that one was in my sister's name. The vacation before that was in June 2009 and my discount was for my Visa Chase Rewards card. The last actual pin code I recieved from Disney was in 2005! Each one after that was related to either my Visa card, somebody traveling in my party or a general public promotion.
Funny, now that I bought into DVC and do not make reservations through CRO, I receive a pincode in the email about every 6 weeks.