I would only do this as a prank we are both in on. If she proposed to me, I would tell her to get up and let it happen the way it's supposed to happen. :-)
But what I think people are missing here....It is not because that it goes against a mere ‘social construct’ or ‘tradition’. Unless the woman is going to be the great provider in the relationship, or she will have, or has equal amount of funds...you don’t beg for someone to take care of you for the rest of your life.
Also, taking a knee is stupid as a tradition, for either party. You go into a relationship as equals when you realize that you will have a division of duties. You will go in as teammates striving for higher together. You should be walking shoulder to shoulder, and, hand in hand. But, in no case, should anyone beg.
