not sure the AA is really that extreme, maybe 2xAA or 4xAA, couple that with the downscaled screens I'm not surprised the AA looks almost perfect.
I was just reminded that this is an UE3 game. That being the case we should expect no MSAA. While there are a number of ways to limit edge aliasing, shots of UE3 games with MSAA are almost certainly PR shots due to the performance penalty of MSAA with UE3.