Greybar said:
When in doubt, go by the book. Probably a good call.
Except of course,the spell isn't in any book. (Not in any that I know, at least). I'm fairly sure it's a Cydra homebrew spell.
By strict interpretation of the rules, it will probably work. And considering the resourcefulness of the players in coming up with this solution, it might also be the correct call to allow it at this time. But personally, I feel that the loophole granted by Superiour Teleport is even more powerful than, for instance, a Discern Location. (It's mostly a combination of Discern Location combined with Greater Teleport)
The *real* trouble, for the PCs at least, is when NPCs start using/abusing this. Also, all normally available protections from Scrying/Divination magic are no longer suitable. This will probably lead to a "Magical Arms Race"*, where there will be a new version of the spells which closes this particular loophole. At least, until the next exception is found. Personally, I think I would say the proper school for Superiour Teleport is probably "Divination [Teleport]". Or you could just houserule that spells can be part of multiple schools at the same time (as per the epic spell seeds).
* [rant] This is something I really don't like, and feel that D&D already gravitates too much towards. I feel blanket immunities for all sorts of things are way too easy to come by. (Deathward/Soulfire vs much of Necromancy, True Seeing vs Illusion, Mind Blank vs Enchantment, Energy Immunity vs Evocation/Conjuration energy spells). Instead of immunity, I think it would be better to grant a bonus on saves.
Fortunately, they are already starting to create countermeasures for some, like Piercing Cold in Frostburn vs Cold Immune (and a Fire version in Sandstorm) [/rant]