I think since most people get quite annoyed at players who sit up there I'd say it was bad clipping (or rather: a lack of clipping)
There are quite a few of these that I know of.. I'll get on to them eventually
Also, can everyone resize their images before they post them so that we don't break the forum whilst the page is loading
When we saw that update "fixed clipping issue on 2fort" i think we all knew what they were talking about..
A shame i've missed some of the others, it would be amusing to know what they were. There's a gap under the ramp in the ramp room next to red spawn, you can see the skybox, spies can also zap sentries through the ceiling/floor here which makes it even worse.
A Boojum Snark: Don't listen to grazr he is probably drunk