Orikoru
Tour Winner
Who the hell does that!? Most people I've played with for a long putt just have a look from behind the ball and give it a whack! If I saw someone walking around looking at every angle for a 30 foot putt then I'd be moaning they really are wasting time.It doesn't waste time.
In your two ball scenario, both with long putts, unless they are both terrible putters, they will want to look at the putt from a couple of different angles, and probably from behind the hole as well. In which case, one of them stays there while the other putts, and then while the first one walks up to mark his ball, the other one walks back to his.