I just found this in a list of changes to the Ohio Revised Code's bicycle laws, effective 2006-09-21.
4511.31 Hazardous Zones
Allows for the crossing of a double yellow line in instances when drivers are approaching a slower vehicle (bicycles, horse-drawn buggies, farm vehicles, etc.) proceeding at less than half of the posted speed, as long as the faster vehicle is capable of passing without exceeding the speed limit and as long as there is sufficient clear space in which to do so.
In other words, my pass was completely legal.