Any CEO doing this for the right reasons - I.e., to help ensure the product is good - would whip the marketing department right into shape and tell them to keep a lid on it.
In this case, the marketing department was not involved, at least publicly. CNBC is reporting this from an internal email they got their hands on.
This is good, right? Then a team of <trolls/activists> can all arrive at the same time and order a big pile of 'secret menu' 19-ingredient monstrosities from the CEO.
Social Media viral coefficient may have been higher with a quieter announcement and the CEO just showing up leverage social media managers.