Since v8 you could place spawn bricks and you wouldn't be able to spawn with the brick outside a minigame. After v9 you could plant a spawn brick and use that as your spawn outside a minigame.
Being able to use a spawn brick outside of a minigame broke a lot of map boundaries. When I block off a secret area or the window from the bedroom because I don't want someone building there they just plant a spawn brick, ctrl k and spawn right inside that area.
In interior only maps like Ikea house, buildbox, ect. Anyone can plant a spawn and get outside of the map itself.
In my recent map (fallout 3) I added an invisible barrier preventing anyone from leaving the area. However they can leave it by planting a spawn brick.
