The date is usually because that's an estimate for when they expect to have your papers ready. If they're not ready, theres nothing you can do. You can them before and if you're lucky and they answer and your papers are ready, maybe they'll let you pick it up early.
I usually book a hotel for the night before, but small hotels have stopped filing tm30 because they have no foreign customers. So I'm still shopping around.
You're idea is good, but there will be no tm30 on file for me, and I'm concerned they will say I need proof of where I stayed previously.