The whole "yield if there's no traffic, stop if there is" discussion is kind of missing the point of a yield sign. If there's no traffic, there's nobody to yield to. If there is traffic, you yield - this may or may not require you to actually stop.

In Europe, almost every intersection without a traffic light or roundabout uses yield signs (applying to both cars and bikes). If an intersection is safe to roll through, why not apply the rule to everybody?