I can understand the uneasy feeling that one can feel when presented with a room service bill with a delivery charge and mandatory gratuity already included in addition to a request for an additional gratuity. I simply review the bill, making certain that a gratuity is already included and write "Included" on the line requesting the additional monies.

I have asked, on occasion, why the additional line is included, since the gratuity is already noted on the bill and have been told (I realize it is simply to provide more revenue to the service personnel) that the tip is shared by a number of people, so the mandatory 18% is not received solely by the room service personnel, rather a small percentage, due to the sharing with other staff members. Whether I believe this explanation or not, I usually do not include an additional gratuity unless the service was exceptional.