Insurmountable Waist Height Fence (InstanceTopic, 7)
From Compile Worlds
Insurmountable Waist Height Fences crop up in virtually all games that aren't platformers (as those actually have decent physics... well, with a few exceptions). They are yet another product of game designer laziness.
The most extreme examples include bird-riding warriors being unable to just fly over fences tall as they when they march.