The thing about the scrying spots is that they are random. Much in the same way as harvesting nodes and the little glowing question marks that we all love to find.
In my opinion, putting them on a map would be completely useless and a waste of time, since the location is never going to be correct. True, you could label a 'general' spot where the spawn around, but that's still just asking to clutter up the map.
Then again, maybe if the interface included some sort of option that let us toggle what POIs were shown on the map......hmmmmm