Your explanation for her conduct is condescending. She was actually trying to take photos of President Trump and the college presidents without blocking the view of the pool cameras.
The pool cameras repaid her thoughtfulness by photographing her in the foreground instead of focusing on the historic meeting in the Oval Office.
Trump was keeping a campaign promise to focus on supporting HBCUs and signed an executive order about HBCUs soon after the meeting.
The question was about her sitting on her knees and somehow it seemed "unbecoming."
That is how someone acts when they are trying to make others feel comfortable. She did not stand as the Queen of England or Hillary for that matter.
She is a woman who tends to put others at ease. I happen to know the woman in question.
You do not know what you are talking about.