> In a traffic jam situation, all-way stop is a "blocked intersection" if every vehicle obeyed it strictly (if there are cars coming from every direction, nobody has right of way and you can't apply the rule of yielding right).

The first arrived rule (which applies before yield right) is usually unambiguous in a traffic jam situation (since it will also be the position where the last car went the least recently, and everyone at the intersection will have been close enough to see through the prior cycle.)