The fences aren't really a big deal. We have 700+ airplanes, and the CAL side is fenced off 25 of those (3% of fleet roughly) and the LUAL pilots initially fenced off only 8 787's (1% of fleet).

Most pilots aren't bidding across legacy boundaries anyway. The 777s, 757/767 and guppies are mixed fleets, since the UAL side starting getting the 1st of its 100 guppies last year and there are already 30 of them.