Actually Roger,
I figured that we were pretty much in agreement all along, Your statement just gave me the opportunity to vent. About the only thing that I would disagree on (and I'm sure that I'm in the minority on this) is the notion of waiting t see how far the runner is out before deciding on the base award.
I believe that the umpire should always make an immediate decision as to the base to which he is going to protect the runner initially. Now, that immediate decision can be adjusted based on "post-obstruction" evidence. And that adjustment can go both ways not just in favor of awarding additional advance bases. Post obstruction evidence can actually result the loss of an awarded base. Consider the following play:
R1 on 1st, batter hits a gapper into right center. R1 has to alter her stride to go around F4 who is standing in the baseline just watching the play (instead of going out for the cutoff or covering 2nd like she should be 
). At the time of the obstruction, I immediately decide that I'm going to award R1 third base. However, as R1 rounds 2nd, she trips over the bag and falls down, (the tripping and falling having nothing to do with F4 who was well away from 2nd base when the obstruction occured).
Due to this "post-obstruction evidence," I might be inclined to modify my initial award of protection to 3rd base back to protection to 2nd base only and if the runner tried for 3rd and was put out, she would most likely be out. Now I will say that I make my new judgement based on the position of the ball and the runner when the post-obstruction event happens, I do not wait to see if she is out by 2 steps or 10.
--SamC