The true debate on this is does the PU call obstruction are does the PU just mentally note the obstruction and then if asked by the BU give the information. (Based on OP the runner should have been placed at 2nd).
We all know the book says either blue can make the call. However, I know a few blues (one that is pretty high up in ASA, has worked the Olympics and Pan Am games) that would tell you this is the BU call and the PU should just note and help if asked.
Let the debate begin
