For what it's worth

[CecilOne]

Originally posted by WestMichiganBlue
Interference? I suppose if the ball is on the way and you knock the catcher out of the play; and the ball get by and other runners then advance another base, maybe you can call interference. But the catcher did not belong there in the first place so why are we rewarding her with an out?

I've got obstruction; award the run, then eject the runner.
WMB

It is penalizing the runner, not rewarding the catcher.
If the catcher was truly guilty of obstruction (impeding the runner), then that's what it is, up to the point when the runner deliberately or flagrantly crashes the catcher (or any fielder) and then it's interference and USC.