Arriving in town the day of my appointment:
I will call the apartment community the morning of my appointment (if it is in the afternoon) or the day before (if the appointment is first thing in the morning) to confirm my visit with the target. If I do that and the target either doesn't show up or passes me off to somebody else (I'll protest a little), I've NEVER had the MSC not pay me. That's out of my control and the MSC fully understands that. I explain what happened and shop the person with whom I am left.
Adding apartments late:
I've never had and MSC demand that I take a shop under the threat of taking others away. If the place is truly remote, they are putting at risk losing you from the other shops, too. Perhaps its how I plan my routes and communicate up front? Let's say Walesmaven's Wobbly Writers and I agree that I will do five shops in Antarctica for $5,000. I then immediate ask if there is anything else in the area that they need done. I clearly state that I want to fill my schedule, but want to verify that their needs are met before I fill it with work from other MSC's. Once they tell me that there isn't, I clearly state that I am planning on committing my free time to other work.
I then reach out to other MSC's and start scheduling time, making it clear that I'm on a route for the great WWW MSC and figuring I can help other MSC's with any shops they are struggling to fill in Antarctica. Of course, I'm clear with what these shops need to be in terms of payment and types of shops. When these MSC's offer me work, it is very much with the understanding that I am in control of my schedule. If an MSC asks me to pick up a targeted shop, if I want the shop, I explain that I will be in that particular neighborhood on exactly one day an will try to set up an appointment, but can't promise success. If they need a promise, I thank them for the offer and say that I fear I would not be able to keep such a commitment...
As my schedule fills, should the WWW approach me with another visit, I look at my schedule and make an honest effort to see if I can get it done. However, I explain that I have made commitments to several other MSC's and that, once I make a commitment, I don't break it (even if a better deal comes around). Every scheduler I've dealt with has respected that.
I've never taken a route where the MSC was in control, so I can't speak to those dynamics well. However, I feel like I can generally do better financially if I am in full control.
Hard work builds character and homework is good for your soul.