obstruction - award a base?

[peter_s_n]

An odd(?) play I saw - Little League. (I was 'spectator')
Batter hits ball to third/short and overruns first with no intent to go to second. The throw from third goes by the first baseman. The second baseman, attempting to back up the throw, collides with and unintentionally trips the baserunner during the 'overrun'. The ball ended up against the fence, the runner ended up face down on the foul line, and play stopped.
Additional info: Left field should have backed up this throw. (kind of odd for the second baseman to be backing up this throw). The second baseman was running and stretching for the throw and ran right through the baserunner approximately 10-15 feet up the foul line from the bag.
It is questionable as to whether the batter-runner would have made it to second base as the ball settled against the fence near the collision.
I've looked at LL Rule 7.06(a)stating that the obstructed runner is entitled to advance without liability to be put out to the base they would have reached if in the umpire's judgement there had been no obstruction.
Section 2 defines obstruction as 'the act of a fielder, while not in possession, or not in the act of fielding the ball, impedes the progress of the runner.'
I believe the batter-runner to have been obstructed. (is backing up the throw the same as fielding the ball - I think not).
The second baseman (the 'obstructor'), may have been able to pickup the misthrow against the fence to throw the batter-runner out had the batter-runner decided to go. (The right fielder was no-where near the play).
Seems the only thing keeping the runner at first would be 'if in the umpire's judgement' - as it was questionable whether the runner would have made it to second.
The play was not questioned by anybody on the field, therefore the game proceeded without incident.
Could this have been obstruction without no penalty ? It was a trainwreck.