The problem with this issue is it is almost never an even swap or swap to a better seat; the swappers are usually trying to grab an aisle when they have two windows.
See my original post - the first one the poachers had 8A and D; the second one the swappers had 3A and D.
On the first one I am guessing they could have had seats together but wanted exit row.
On the second one in this case it was FCM but it usually is a battefield upgrade.
When I get battlefield I take what I get, it is part of the game. Traveling with my wife next week; nothing but windows or bulkheads available, so if we do get upgraded that is what we will get. And probably not together; after 20 years I think we can be apart for 1 hour.