I must have missed the "sweep", because nothing has shown up yet. But I did get a response:

1. If it's coded as just miles from the hotel, it will trigger the bonus.
2. If it's coded as a Mileage Transfer, it probably won't.
3. There were no threats of locking my account or any other dire consequences; just a thanks for being a loyal Northwest customer.

So, I'm at the mercy of the hotel chain. I'll make no more transfers until I see what happens -- you win some, you lose some.