Sometimes, it's all in how you "sell your argument" to a coach or captain. If you can convince them that the defensive player, while not in possession of the ball, took away the runner's options for their desired base path, then you have done your job.
I know that we've been down this obstruction path (no pun intended) before in other threads, and sometimes, it's a toughie. Obstruction, in my opinion, is still up to the judgment of the umpire, and if you call it, you'd better be able to sell it. Your call, blue.
