Yes there are also other ways to do this as well.
What you are referring too is adding an invisible digital signature using your own certificate authority and tracking the signature checks. More information on signing a document with an invisible signature can be found here but again you'll also need to setup your own CA and monitor it's traffic:
Other ways this can happen occur when people leverage the scripting function within the document to make a call to a unique URL or DNS request to a unique host either or which then reveals the person who opens the documents publicly accessible external IP address. These can be embedded in different document types in a number of different ways and there are many commercial services which offer software just to do this. Likewise there are many penetration testing tools / red team exploitation tools for Word and other document types (.pdf's are more commonly exploited because these can in some cases also give an attacker a remote shell on the system where the document was opened).
Can this be prevented. Yes but not easily you have to really lock your internal computers security down well and either have tight egress rules which don't allow traffic out or block the IP address(es) the documents want to call home too.