I really like the whole idea of bastila as the exile, but there are too many facts pointing the other way. Even for fun, it just seems like a bad idea. i play kotor alot to find out alot of stuff (I HAVE NO LIFE)
On korriban, in the tomb, your character doesn't know bastila is bad.
I really think the old bat would give you a clue your her.
It would be very awkward doing this in game, because of the plot of the game (ie. getting cast out of the order). It would ruin the fun.
You only fail if you stop trylng.