Sidewalk etiquette for people walking in groups and on the left
For the most part, people walk on the right like the direction of traffic. When I was a kid it was drilled to us that right is for walking, left for passing, single file line etc. I change the rules accordingly to geography like walking on the left in Japan and the UK or for the elderly, disabled, children etc.
On campus its anarchy from oblivious people on the phone, groups of people walking abreast at a snails pace, having conversations in the middle of the sidewalk and those who are intent on sticking to their left into incoming traffic despite seeing people walking in the same direction on the right adjacent to them. Occasionally I bump into people on the stairs or at corners because people are main characters and oblivious to their surroundings.
I don't bother accomodating for people who don't follow etiquette anymore. If people are walking into my direction, I would slow down and stop in place. People usually get the hint and correct themselves. If they are still intent walking into my direction then I prepare for a brace and continue on. If you get upset that you got shoulder checked or bumped walking into me thats on you. If you don't want to play red rover then pay attention to your surroundings and stick to sidewalk etiquette.
End of rant.