My parents bought a house a couple years ago, and the previous owners thought it would be okay to put a wall in by screwing 2x4s into the existing drywall of the adjacent walls and putting the sheets up on either side of the 2x4.

They also thought that nobody would notice the fresh paint and fresh plywood used to cover up massive amounts of mold, and when it was discovered after the first day they shrugged and went “oh we had no idea” and a judge believed them.