When a Teleport is foiled, does the affected character end up somewhere randomly inside the 20ft radius area of Conjuration Foil or somewhere randomly in the range of Teleport (100s of square miles)?
I believe you end up somewhere within the range of the teleportation effect. But it’s a “similar location” so it shouldn’t usually be that far, unless you were going somewhere really generic.
As per the spells description...
All creatures in the area gain a +4 bonus on saving throws against teleportation effects. If any creature would enter or depart the area via a summoning or teleportation effect, that creature takes 1d6 points of damage per spell level of the triggering effect (or half the HD of the originating creature if the effect has no spell level) and arrives in a random similar location within the triggering effect’s range, rather than the intended destination.
A successful Will save halves the damage and negates the altered destination.
Similar location within the teleports range. The spell that triggered the conjuration foil is used to determine where the affected party ends up. So while it can’t prevent one from teleporting away it does stop them from going where they wanted.
Well...that's disappointing.
Thanks.
Pretty decent for an immediate action.