I am not really concerned with ads. I am concerned my current email content has been shared with ad providers. It is possible to trace a person's active by inferring the ads that has been served to this person.
And to say those are not tracked is like saying you bill your customerA about the amount of ads you served while telling them you didn't have any prove that you didn't serve more competitors ads (customerB) than customerA. And there is no proof you pretend to show customerA's ads with phony IPs or vague counting number.