I have a player who has taken the Blessed Words stunt out of the Baltimore section of the Dresden RPG book. (Multiple characters have it, sample char at page 379) At first it didn't seem like that big of a deal to me -- given time to pray, he can lay an aspect on the scene. Pretty fair. Basically a transplanting of the alertness ability to conviction.
Then he started wanting to do things like praying for rain. Or cops. And look! A siren goes off, answering his prayer for reinforcements in the middle of the fight!
I'd assumed -- and he didn't -- that the aspects would be limited to the type of things conviction does. Faith. Mental fortitude. Etc etc. He's going, 'well, I'm a priest and God answers my prayers!' He keeps arguing that he's not doing something that alertness couldn't do, but the point is that this is conviction not alertness. Alertness is about noticing things on the scene, it can do things conviction can't -- and vice versa.
We're going back and forth over it, and to me, what he's wanting to do is a power. And possibly -- though I haven't mentioned it yet -- a more than 1 refresh power. I mean, the ability to just make things happen...
So where is the right limit to this ability, and how do I explain it?