This whole thing feels like a solution in search of a problem. I read lots of theoretical examples but I've not heard one person say they would actually put in for a swap. The biggest issue is getting stuck where you don't want to be. Yeah it sounds great to bid to MSP or DTW for the summer and ATL for the winter. Problem is you need to have someone willing to do the opposite swap both ways, and goodness who wants to spend summer in GA and winter in MN? By and large people end up where they want to be through the AE process. The theory of sport bidding sounds good but I think the risk of getting stuck out of your preferred domicile for some period of time are too high for most people to bother with. Generally pilots flow out of junior/crappy bases to more desireable ones and don't really care to ever swap back. And again that's the issue - for every swap there needs to be a pilot wanting to go the opposite direction, and I just don't see that demand there.