I can walk off the map. I don't know if this is intended or not, but still, here it is:

http://gyazo.com/86e615fbd86f5ad07461a4c739f8d02c

Which map?
Meph's map also has the same thing.

If they are user maps its because the person that made it didnt put up the right kind of wall 

Ohh right I see, well that clears it up. thanks Sdiddy

That's Area 1 of the Land of the 100's isn't it? That was the first map I made, got the dimensions wrong but didn't realize it until I had placed a bunch of npcs. Too late to change it. I was wondering when someone would discover it

Yeah, those tile pieces are walkable. You'd need to use tile pieces that are non-walkable (need better terminology) to stop it being possible.