Yet another OBS scenario: base path and home plate

[NCASAUmp]

I know OBS comes up a lot on this forum, and pardon me for tossing this out there. However, I have one question for everyone...

Do you consider the base path to stop at home plate? Or do you consider the base path to be through it? Consider the following play...

R1 on 3rd, R2 on 2nd. No outs. B3 hits a pop fly ball to the outfield, easily caught by F9. Both runners tag up and attempt to advance to the next base. F9 throws to F2, who is standing just off the 1st base foul edge of home plate. B1, seeing F2's position and worrying about a possible collision, slows down enough to be noticed by PU. F2 then catches the ball, turns, and tags B1 on a very close play.

Would you have obstruction there? If not, at what point would you consider F2's location to be obstructing the runner? Actually on the edge of HP? In the middle of HP?

I'll post my answer later (and I promise I won't change it after reading everyone else's!).