Its a difficult issue, that of where to stand when someone else is playing & where others should stand when we play...

.... Nothing is worse than someone standing just in the line of site, than someone, just outside of that peripheral vision.

Though to be honest to me its not so much the position of someone, than the invasion of personal space & as soon as we pick up a club, the boundaries of personal space increase three fold.

There is certainly good reason to spell out the exact requirements of of ourselves to others when we play, for the simple reason that we would expect to (or should) abide by others requirements, whether as regards to the rules of play or simple curtsy.

I think most of us know when we've done something wrong, as regards to our own conduct when others are trying to play.