This along with Jon's suggestion of reminding them you are a Titanium elite member and what it would cost them to walk you. I doubt that every person checking in that day will be a Titanium or higher. If you remind them of the cost to walk you, only if they have no other choice will they do so as it is so expensive to do that. And checking in later means they probably have already checked-in lots of others. If they forget about your elite status and run out of rooms, you may get walked no matter the cost to them.