Odette still hasn't quite gotten Sympathy teleportation figured out, so if she wants to talk to her sister in person instead of over lovely elf-derived telepathy she still has to physically traverse the space between there and where she starts out, and the windows into Illia's throne room are more decorative than openable, so she has to use the doors into the throne room.
Those were the doors to her sister's throne room. Even if she hadn't built the place she uses those doors on a regular basis.
She didn't even put a bar anywhere in the palace, let alone in the throne room. And she would have noticed if someone else put one there.
Well, this bears investigating.
She wanders in, in the general direction of the actual bar.