Sorry, another OBS play 
:
Short grounder to F3, F4 tries to cover 1st, ends up a few inches behind base, foul side, directly in BR path.
Meanwhile, F3 fields, keeps ball and backs toward base, leaving no inside room for BR.
F4 clearly in the way of BR, never having ball.
True or false?
As long as BR slows, “pulls up” slightly, or hesitates; even if no turn; OBS is the call; even though F4 is slightly
past base.
ASA rules priority, but any other you think is different.
This topic will not be helped by HTBT responses.
Please do not use it to chide or demean each other. 