I agree with Andre, first off the Japanese are especially honest people. Had this been anywhere else, you'd be lucky if the cab driver returned it, let alone the hotel manager 'admitting' he has the phone and then offering his assistance. Obviously he's done some work to realize he can't send the phone over because it has a Lithium battery, this isn't something that would be considered common knowledge.
Secondly, the phones to the US are shipped from China not Japan, and what if the manager really wanted to phone, all he'd have to do is say he doesn't have it.
Finally, the English is funny. But then again, can you speak Japanese?