I've never actually walked into people, usually after 2 or 3 you look at each other and smile and then one person steps to the side or both and then you go, no you, ok.
it definitely should smile before/while driving into your legs as well as when standing waiting for you to walk around. It can also mark you with the laser pointer to indicate that it does sense you. Communication is the key.
The facial communication is only necessary because we're negotiating as two people who want to go where the other one is. When it comes to bots they can be forever deferential and always yield to humans.
I understand yea - when it comes to a robot and a human though the human doesn't need to yield. It'll probably take some time to train it into people but humans should always have the right of way.