Originally Posted by Mahalo
The problem usually occurs when the charges on not on the initial invoice but billed after you leave. For example if a guest decided to consume something from the snack or mini-bar the morning they are checking out, it won't be reflected in the bill when checking out. Once the mini-bar is checked later that morning, the hotel then places the charges on the invoice or on a separate invoice.
... or just bills an additional unexplained amount to your credit card without ever issuing another invoice, or any kind of explanation of what the additional charge was for. And then ignores your follow-up inquiry. (Happened to me at W Union Sq recently.)