I can't imagine having planned or thought out rules of behavior in place for when I go shopping. Life is to short to sweat the small stuff and why waste the energy it takes to be rude or hateful?
More than once, my husband has had to say to me...babe someone is trying to get around you. I just step to the side as I look behind me and say, sorry about that. More times than not, the person will go around me with a smile and say thank you.
It would never occur to me to deliberately remain in someones way knowing they were wanting to get around me. And, all because they didn't say the magic words, "excuse me".