Technically, there are indeed "invisible walls" (and if you were stuck, you were not able to walk backwards).
But their existence is "out of character", and a hopefully temporary restriction of the movement, during the long development of PlaneShift. But leaving the maps beyond their technical limits has to be avoided "by all means".
In my personal opinion, it is a little a lack of game design if they become too obviously unnecessary, like that corner in the middle of a road near the exit of the forest in the north of Hydlaa. But they will be fixed sooner or later, at least before Version 1.0 - probably by visible steepnesses unable to climb... fixing heightfield maps should not be too hard.
