Why would they need to subpoena Microsoft and why will Microsoft hand them the data if someone doesn't like my meme? I understand what you are trying to say but it does not make a whole lot of sense even from Microsoft pov. They are not bound by law to hand over personal data to anyone without a warrant issued. If a warrant is issued then it is their lawful duty to give that data, the same would be done by you if you were in their shoes or your office or your family. Law is not optional to follow. But Microsoft doesn't need to do watermarking on memes to track you or to do this as a war against "internet anonymity".
You can incentivize cooperation without having to compel action with a warrant. This sort of corrupt quid pro quo is quite common, in other countries at least...
I would say the watermarking is not really a puzzle piece at all when it comes to the surveillance state, which was my point. They don't need watermarking to know who you are or to get information about you. So why would they work on this really visibile method if their intention was to progress the survelliance state? Microsoft with all their resources (and assuming it is an evil corporation purely acting from the state's interest to spy on you) will use this to track you?
