Many thanks to you both for that. As a matter of interest, I have booked all inclusive (fare, taxes, tolls and tip) limo services from NY to JFK. Despite the tip being included, on arrival at JFK the drivers seemed to expect an extra tip.
In order to avoid the evil eye, on a subsequent booking I told them to deduct the tip ($15 off) and gave the driver $20. He was over the moon and told me that the customer is told it’s all inclusive but the limo firm never gives the tip to them.