The team that the "bid thief" would knock out is whoever is the final at-large team on the S-curve. If that happens to be a team from the same conference then so be it. However, if BYU were theoretically the 2nd or 3rd to last team in after a loss to St. Mary's in the conference semis and St. Mary's went on to win the conference tournament St. Mary's would end up taking the spot of the LAST team in at that point. There is no quota or determination for how many bid a specific conference "deserves" which is what your post is implying.