to make this an official Hilton Thread, I can say that this happened to me at my last hilton stay. As confused as I am, I NEVER add an additional tip as it is plainly listed as a gratuity. If it is not a gratuity, it is up to the employees to get the wording changed so that the guests are not lured into thinking it is the waiters tip.

However if it is a tip, then what more do they want.