First things first, Interaction Priority was something that appeared in the
PTS patch notes 7.1.0, and to me at least, went by largely unnoticed. It promised to change the interaction priority so that the game would let us interact with crafting stations and bankers, even when other players' pets and companions were in the way. So far so good!
However, I only recently discovered that this has some HUGE and unfortunate consequences for housing. Most housing people are used to being able to block off doors in their houses, to stop people from entering certain areas of their house that they don't want to use. However, as it turns out, the priority system means that players will be able to still interact with these doors THROUGH items you have placed there to block it. This includes door furnishings, walls, fountains, platforms, and pretty much anything you can think of EXCEPT crafting stations, which still take priority over doors in the priority system as it currently stands on the PTS.
Case in point: place a huge wall in front of a door, and the door can still be used.
Place a door (furnishing) in front of it, and the house's original door can be activated through the door that you placed.
If you place an outfit station inside the door though, EVEN THOUGH the station can't actually be activated with this placement, the game will try and target this crafting station first, and thus be unable to activate the door. So that's bad news for you, my dear housing enthusiast friends. Blocking doors is going to be very expensive in the future.