Gratuities added to a hotel bill, because they become part of the lodging cost (allowable up to State maximums).
15-20% tips for meals, within maximum meal rates, whether or not the receipt shows the tip.
Tips to cab drivers, as mentioned in Receipts are allowable.
Tips to bell boys, parking lot attendants, room attendants, or any other situation where there is a choice made by the individual to tip. According to the State Comptroller's Office, such tips become a personal expense.