Your company sends you to a 3-day conference out of town. They will reimburseme parking, but not vallet parking or tips.
When you arrive at the hotel they booked for you, you find out it is only vallet parking; there is no self-parking. Parking turns out to be $26.05 a day ($23 + tax).
How much would you tip the vallets who parked your car on day one and returned your car on day four? Does it make a difference if you would have self-parked had that been an option?