Once upon a time, I would ship word docs with a remote image using a unique URL that I host. When someone opens the word doc (and accepts remote images) the URL

Once upon a time, I would ship word docs with a remote image using a unique URL that I host. When someone opens the word doc (and accepts remote images) the URL is fetched and I know when someone opened a doc that was destined for a particular recipient. It's quite interesting when the doc intended for a specific recipient is opened in 15 different geographical areas. Even more interesting when that specific recipient was under an NDA. My question to you is if this should be made illegal? (since it is the same action facebook appears to be doing)