Depends on the watermark. The current watermark uses a DCT to add a bit of undetectable noise around the edges. It survives resizing but tends to fail after rotation or cropping.

A robust rotationally invariant repeating-but-not-obviously micro watermark would be quite a neat trick.

Watermarks can be made to be pretty robust, though having an open source detection routine will make it much easier to remove (if nothing else, if you can differentiate the detection algorithm then you can basically just optimise it away). The kind of watermarking that is e.g. used for 'traitor tracking' tends to rely on at least a symmetric key being secret, if not the techniques used as a whole (which can include more specific changes to the content that are carefully varied between different receivers of the watermarked information, like slightly different cuts in a film, for example).

Microstates vs macrostates. Doesn't it depend on the basis for the encoding and how many bits it is? Watermark, we usually think of something in the pixel plane, but a watermark can be in the frequency spectrum, and other steganographic (clever) resilient basises.