Gez said:As I have explained a lot, if they had teleportation magic available, they could have used it to go back home (but not before Sauron was eliminated, because it was clear that in Tolkien's house-rules, the use of powerful spells is detected by other spellcasters), but not to move to Orodruin. Not possible. Not at all.
- Gandalf's knowledge of the Mount Doom of now was most certainly imperfect. Volcanoes are mutable places, strongholds of evil are as well. Not having a clear mental picture of what the destination was, he risked misshap or other teleportation errors.
- Places with strong physical energies can make teleportations hazardous or impossible. A volcano qualifies as a place with strong physical energies. So, not only was teleportation impossible or hazardous because Gandalf's familiarity with the place was insufficient, but it was even more "hazardous or impossible" because there's lot of hot fiery lava and other telluric manifestations.
- Places with strong magical energies can also make teleportations hazardous or impossible. The mystical birth-place of the most potent ring artifact, only place where it can be destroyed, and just beside the fortress of what could be approximated to a Demon Prince in D&D terms, happens to genuinely qualifies as a place with strong magical energies.
There's no less than three factors that would make a teleportation right before the pit a very bad idea, or something impossible to do.
... of course, you could just ban teleport, and save having to come up with these handwaves in the first place.