11if you talk arabia, if you let enemy wall, you too slow/not aggressive enough
Walls are both good and bad - it all depends.
Later UP versions (after the 1.1 release) might have a "No walls"-gamestyle.
"Michi-Style" (no passing center of any map with any units until x-minute/age)
And options for "No-Castles", "No-Towers", "No-BT"