Today we had yet another example of someone accidentally asking a question on BH.SE that actually belonged on Christianity.SE. "dæn" ;-) recommended to the OP that he ask it over on Christianity.SE, but is that really the best we can do?
In such cases, where it is clear to the team that the question belongs on our other site, I think we ought to migrate it over there for them, and not just make the recommendation. Here are some good reasons for doing this:
The OP doesn't know / have access to migrate it, so they'll have to manually create the new question over there. This means we're making things more difficult than they need to be for our "customers".
Christianity.SE shows users this kind of courtesy, and as a sort of "big brother site" to ours, I think we should follow suit
By migrating it ourselves, not only are we introducing the user to Christianity.SE, but we are also advertising BH.SE on that higher-volume site