Just tested this with https://emailprivacytester.com/ and it failed
Even though it claims to not load remote content by default, and pops up a "Load Images" dialogue, it actually loads content from the html5 video and audio tags immediately.
So whilst this doesn't work unless the user clicks "Load Images":
<img src="http://TRACKING_URL/">
This does: <video autoplay="true" src="http://TRACKING_URL/"></video>