Imperial Dispensation is kinda up in the air, in that regard.
The Emperor might just take us at our words, since we are a hero and know quanity and all, and just grants us dispensation no problem or questions asked, or he might decide he needs more info and go ask every single cult leader about this whole "Dhar in waystone" things, letting the cat out of the bag anyway, and eventually refuse it, or demand our Great deed as payment.
For the people who are looking to keep this totally secret, Imperial Dispensation is both the greatest reward and the biggest drawback, it's the classical gamble choice of this turn. Which on a normal turn, would been a perfect place to have the Gambler coin on, though this is much more of a sudden choice, so we can't plan around it.