I would imagine there will still be some crossover on trips between systems (ATL crews doing flights in the IAD system through LWB, or vice-versa) like we are doing currently, but I don't see ATL crews being allowed to bid for lines in IAD. Open time pickup definitely, but that's about it.
With the way the CBA lays out Staffing Bid procedure, this will most likely result in the downgrading of many junior CAs in favor of senior FOs getting upgrades. Don't count on using displacement rights to hold your seat, they are only as good as your seniority. I wouldn't doubt that many DECs will likely quit rather than accept demotion. This could get messy. I had a feeling a few months back when they did the SB in July that the reason they were waiting to move people was that this one was coming. No point in paying moving expenses when they were just going to do a major reshuffle a few months down the road.