Huh, this thread died quickly
Well, after seeing how you could stack sandbags and stuff on top of each other, I decided to test it a litle on a server.
Here is my fort, with people stopping to look at it rather than killing each other
Here is my attempt to start a new better one on the next map, but I had to leave.
And here is my latest attempt again to make a nicer one. I got bored