It is no different than most things in life. Think ahead, be polite, be discrete, and there should be no problems.
As to why do it--because there are a lot of ladies in tbis business I care about and I want them to be safe. That is why I offer to drive them if it is late, or call (and pay for) a cab. Is transportation"included in the price"? Probably. But it is a small investment of $20.00 to make sure she gets home safely.
Of course the best option when it is late is for her to stay over, have breakfast, and go home the next morning.