Had this happen a couple of times. Once, waiting for her to arrive at my place (incall); the other I actually had been to her place several times before. Got there at the scheduled time, knocked on the door lightly, several times and no answer. Drove a long way in a rainstorm. These were in the days before cell phones. Just chalked it up to being part of the hobby and stashed the cash in the piggy bank for next time.