And when people see Trump shake hands with the Queen without bowing, they will understand who is in charge. Trump will most definitely not be rude, but he is the leader of a superpower, and she is just the wealthy head of state of a friendly country. So he will not defer to her power at all. But she is after all a lady, and Trump is a gentleman so there will likely be something that the press misinterpret because they do NOT understand how gentlemen should behave with a lady.
And Melania likely will NOT curtsey. She might even give Elizabeth a hug. It would be real interesting if Melania speaks French with her.