Adding a guest/room, but not 100% sure they can come

[MoonFaerie]

One of our friends might be coming with us, but she's not sure yet is she'll be able to get the time off. It might be 2ish weeks before she gets a for sure answer. Since we're staying at a deluxe, I'd really like to use the 40%. Would it cause problems if we go ahead and add her now, before the pin expires in a few days, and just drop her and the second room later if needed?