It's not just cliffs, but corners of walls, bits of walls that jut out from the edges, inn doors, miscellenous placeable objects, crypt area edges that align next to a hole. Hells, even Borval saw me get stuck up on one of the two tower plinths of the gate between Midway & the Village of Barovia due to being pushed by the door. On a side note - it's a walkable spot up there! A trap door and a doorway and stairs leading up to it would be awesome for the view for either side and guards that manned those towers.
There are many ways to get stuck. Easiest way to make this @makesafe work is if it ported to an OOC area after a long timer where you could then return to your last stored safe location or faction base, (not last rested location though), and it was only useable once per reset.
The timer and once per reset would deter people trying to use it as a means of fast travel. I think this would be the only thing people would try and could abuse this way for, so logs could be kept of people that use it and recorded, if it's used too often could warrant questioning the person using it by bringing up the logs. If they're very good at legitimately getting stuck then you have someone you could talk directly to on bug fixes on how they get stuck.
Trying the other various means of getting unstuck that I'd listed earlier would still be the preferable method than having to do-over from a faction base / safe location point.