This isn't really anything special. Using bugs to track email open rates in any kind of marketing-related email is standard procedure in any sufficiently large company. There are a lot of perfectly benign ways to use tracking bugs in emails, and it's somewhat silly to assume that AT&T is being malicious with it. If you hate and distrust AT&T quite that much, then perhaps you shouldn't be giving them your business.
Agreed. I would be shocked to see an email from any mass mailing that did not include this kind of tracking. If you don't like this sort of thing, turn of images and HTML.