I had a play as PU similar to this over the weekend, although I didn't yell "Whoa whoa" during the play. I can't remember if it was R1 and R2 or if the bases were loaded, but two runners were trying to score. As the first runner is trying to score, the catcher goes up the line without the ball and they collide, so I have obstruction on F2. The ball gets there shortly after the collision and ends up going to the backstop, so the second runner comes in and scores as well.
The offensive coach wanted me to say something to the catcher. I told him I called obstruction and that I couldn't really do anything else since it wasn't malicious. Meanwhile, the defensive team's fans are yapping that the runner lowered his shoulder and ran their catcher over.
