[Bluefoot]

Hypothetical situation, NFHS rules, YOU are the FU:
R1 on 1B. R1 tries to steal second base on the release of the pitch by F1.
F6 awaits throw from F2 by standing directly on top of 2B.
R1 arrives at 2B while standing up and running, before the ball gets to F6. R1 and F6 collide on top of 2B. You signal OBS and hold out left arm. R1 is not yet tagged out with the ball.
R1 does not stop running and tries to advance to 3B.
(If R1 is safe at 3B, any OBS would be over.)

But what if R1 is tagged out by the defense between 2B and 3B - what is your call then? Since F6 did not commit the OBS between two bases, but rather directly on a base, do you have R1 protected only between 1B and 2B, and/or also protected between 2B and 3B? Although it may have seemed initially that R1 was intending to advance only to 2B, R1 is entitled to try to advance to 3B. F6 obstructed both R1's arrival and departure at 2B. What's your call: either R1 out, or dead ball and put R1 on 2B? (There's no way to put R1 on 3B, right?)