When the offense figured it out...
 

I apologize in advance for the long post...

R1, R2, R3, 1 out. Batter hits a sharp one hop that hooks inside the 3B bag. F5, much to his surprise comes up with the ball and attempts to tag R3 who is diving back to the 3B bag. F5 does not tag the runner, but steps on the bag. My partner correctly calls R2 out on the force. F5 for some reason chases R2 back toward 2B and catch R2, who is already out in a rundown. My partner is still signaling out and verbalizing "He is out, He is out". R2 stops, and is tagged by F6. F6, believing the third out has been made, rolls the ball to the mound and leaves the field with the rest of his team AS WELL AS the offense, who also believes the third out has been made. The offensive coach realizes there are only 2 outs, but not until all of his players are in the dugout. All of the defensive players were in their dugout as well. As the offensive coach runs out to argue the fact that there were only 2 outs, we tell him unfortunately all of the players have left the field and the half inning is effectively over. Whew...

My question is this: At what point could the offense coach realized the mistake and rightly returned his runners to the field??? The offensive coach took our explanation with a grin and indicated he "should have been a little quicker on the draw."

Abandonment!

Depends what rule set. Runners are guilty of abandonment. OBR would have them entering the dugout or crossing the foul line depending on which side of the field their dugout is on. FED would be less lenient in the umpires judgment of when the runners abandoned their bases. Usually around the pitcher's mound or before they enter dugout, depending on which side of the field their dugout is on. (which way R3 and R1 are heading is what I'm getting at) They only have to get one of the runners for abandonment for the third out.

J/R says "progresses a reasonable distance toward his dugout.. and indicates no intent to reassert his status as a runner has abandoned his effort to run the bases." J/R then gives several examples of runners who are called out for abandonment who have neither crossed a foul line or entered a dugout.

I believe Evans uses something along what I was quoting. Not all leagues that use OBR play on fields as big as the Major Leagues. I've never had it happen in a game, but I would try to use my best judgment in determining when a runner had abandoned. I don't have a J/R so I couldn't really go into detail what they have as case plays.

Evans says "reasonable distance", does not mention foul line or dugout. Nice try.

The appropriate ruling is "best judgement" regardless of rule set. Foul line and/or dugout are not relevant.