It depends how far she`s got to travel, and how she`s going to do it. For short journeys the cost is usually programmed into the quoted price, but for longer distances it will probably depend on whether she drives her own car or whether she uses taxis or a chauffeur. My last regular used to drive 25 miles each way coming to me (an hour each way in traffic) for a 3 hour date, and I gave her an extra £20, which I thought very satisfactory.
The lady with whom I am at present negotiating terms doesn`t drive, so she is prepared to come 12 miles by taxi at no extra expense for a 2 hour meet, and I`ll drive her back to sufficiently close to her home for her to walk the rest and preserve her privacy.
I think it`s just one of those side issues you have to negotiate with every different w.g.