I'd recommend calling the hotel. They can add it to the notes the FD sees. Technically reservations can do it, but it could get buried in the wants high floor, away from elevator, extra feather pillows notes. From what I've been told, there's a separate line that the FD sees first that they can create and/or add to - ie, spouse name, checking in first, has pet/knows fee, blah, blah, blah.

Of course if you're doing the booking it for spouse but you won't be there at all so the spouse gets your bennies, that may vary. The property, even if they accept the note, may or may not extend the bennies if you're not there. They're not required to do so.

Cheers.