Boundary Controls are condo items that are simply re-sizable, invisible cubes (once placed) that owners can place in their condos.
If there are demands, they could also come in different primitive shapes, although cubes (or rectangles when you scale differently) would make most sense.
They do not have any collision nor anyone can see them, but once a player is within the cube, they are bound to the laws of the boundary set by the owner.
Things it can do WITHIN ITS BOUNDARY:
Earlier today @carpet_cheese suggested Custom Room Names (http://forums.pixeltailgames.com/t/custom-room-names/27081). Boundary Controls can have names which will indicate where the user is.
Allow/Ban jetpacks. Useful for making different parkour courses, or prohibiting players from accessing certain places normally.
Allow/ban potions. Especially with the potion glitch, visitors can phase through certain ceilings. Although this does not usually cause any problems, some owners also do not want people to escape the intended boundary. Fixing the glitch would actaully hurt a lot of condos because some actually use them to give players more access as well.
Allow/ban eating & drinking. Although this is already possible, it is applied condo-wide. Some of them are great for displays, but condo owners have to sacrifice atheistic for some funny interactions. This gives owners the best of both worlds!
Allow/ban fun equippables, like throwing knives, confetti guns, etc. Most owners don't really disable this because they are pretty fun to use. Some condos even use them as attractions (such as throwing knife contest). However, those who do usually do this because they can annoy other players in different ways (e.g. watching media players). This allows players to still use these fun little items in designated area while not bother other visitors.
The extensions of this item can be limitless.
There already seems to be similar mechanics present in the backend (condos use it for room names, and the Plaza map use it to disallow certain items within the boundary like around the Typing Derby area, so I'm suggesting this in the hopes that it is easy and fast to implement for something that could really bring another level of creativity for condo builders.