Can build inside other towns buidlings that I do not own.

[maze]

You can pretty much lay down "blueprints" like benches inside other players buildings (not houses) like the inn, Blacksmith, carpentry, ect.

Very easy to just do this as a quick grief.
Video: https://i.gyazo.com/dbd6ec317434eefd21f57ab2b7d7dc1c.mp4