Richard, any part of a site coming from a third party is NOT in the owners control. If a hack comes out tomorrow based on images (like that recent jpg hack) then 1x1 images are just as risky as full page ones. Someone breaks into your systems and puts malicous code and suddenly tens of thousands of websites are spewing stuff without the owner's control.
Also, I am sure you are aware that most of the top sites on your lists have no privacy statement or disclosure of third party tracking.
It's all in how you look at it, I guess. Most important, it's my link lists, so my rules
Alex