During the fires in Peloponese 2 summers ago, the King and Queen visited some areas and offered assistance through the Anna Maria foundation. It is a bit tricky to get too openly involved with anything that the government may consider an intereference in internal affaires.
However, I have never seen or heard about anything Pavlos and MC may have done to endear themselves to the Greeks. There was some talk about proceeds from a video of their wedding ceremonies but nothing was ever made public. We know that MC loves to tell about all she does, however any activities she may have undertaken regarding Greece, have been secret, to say the least.