I tend to "plan ahead" and make appointments for both visiting and local providers weeks in advance. For instance, I'm currently booking my December appointments. So Providers that pop up on the local ad section on the 12th saying "I'm here from 13 through 14", I'm usually already booked and funds set aside so I won't see them. Another visiting provider let us know a week ago she'd be in town the second week of December, and I'm booked with her.
Give me advance notice, and I will pre-book. Give me last minute notice, and I'll ignore you. My experiences have been 50/50. Only once has there been a "No Show". I have had cancellations by the travelling providers for many reasons, up to and including "Not enough interest/bookings so I'm cancelling.. sorry guys that pre-booked" which I thought was pretty low grade and so I probably won't ever contact her again the next time she claims to be planning on coming to town.