I'd guess using the hotel's name to put the mark at ease was effective

(Some) Details:

Hotels in a major metro area have apparently been targeted by someone calling rooms and posing as hotel staff. It's been pretty effective, or so I could conclude not just from seeing a friend fall for it but from seeing the actual letter printed by one of the hotels (dated over a week ago) to help patrons get out of the charge with their credit providers.

Withholding details until I've been cleared to provide more. I frankly have no idea how common a practice this is; I just thought it was a creative way to rapidly establish trust with hotel patrons.