You may want to consider adding a “tracking-exception” list. It would be useful to have tracking on by default, but to provide some automatic preset exceptions. In particular, it would be nice to not have tracking set for mailing lists, since so many notifications can come back from them and it's not that important to know when it's been opened. Likewise, it might be good to disable tracking for those you know would object. I know this can be done manually for individual posts, but we often forget. Perhaps a tracking "blacklist" of email addresses could be put in place.