[CelticNHBlue]

Speaking off the cuff, without any manuals in front of me, I would have the following:

Umpires have to continue with their assignments as though no obstruction occurred, therefor, PU has the call at third and kills the play and has the option of awarding or conferencing depending on how much of the play s/he saw. I, as the PU, would only award what I could discern for myself. If my attention was elsewhere, possible trap catch for example, and only knew of the obstruction because my partner made a nice verbal 'obstruction' call along with her/his signal, then I am absolutely going to my partner to determine the appropriate location to put the runner(s). A good crew will also make eye contact following the call as the BU moves to take the BR so that they are both aware of each others awareness of the situation. If the BU feels that the PU is out to lunch, then I would expect the BU to kill the play, from her/his normal location as they track the BR and step in to award as necessary.

What I am getting at in general, is that any umpire with all the information can place the runner(s) when that runner becomes her/his responsibility, but should always consult if they are missing a piece of the puzzle.

Additionally, your example was for two-man mechanics in which runners are less likely to move from the responsibility of the BU to the PU. Also, the plate umpire has everything in front of her/him and will typically be able to make the ruling immediately. I think you are more likely to see this with three-man mechanics when U1 rotates to the plate and has a call on an obstructed runner. It is also more likely that s/he will not have seen the actual obstruction because her/his primary responsibilities are in fact away from where the obstruction is most likely to occur thereby requiring all umpires to conference and determine the appropriate location(s) for the runner(s).

Finally, I would add that any time an umpire not making the obstruction call kills the play; if there is any question from either bench, I will conference to be certain that we get the call right. And it just looks good, too.