Like FLOOR_MASTER suggested, I made some "one way" textures that I plan on using to indicate that certain gates can only be opened from one side (like some of those on cp_dustbowl). I guess it's good to give players a heads-up, especially on a custom map where any minor frustration can damage first impressions.
There's also some "stage x" textures, just for fun.
i personally don't see the need of putting a one way sign on a one way door. they don't do it in dustbowl do they? and it never caused any "minor frustration" when i first played it. it's all about learning the map. they are great textures but the original suggester needs to suck it up.