Hosts are not able to cancel without penalty - in any case they would have a fine of $50 (not sure if per day) if far in advance of the date you are booking. That penalty goes up closer to a date. Also, by canceling you, they should being losing the ability to use that weekend/time period at all, though Instant Bookers do get three cancellations for free a year, but those are intended to be used if the host is feeling unsafe because of the booking (i.e. I, other people, have had a former felon book - I share my home with my children so I didn't want to be a host in that situation if drug crimes/violence/etc were involved). I would be surprised if they could use them just for you booking their room for an unreasonably low rate.
This information might be useful to provide to hosts, because especially newer hosts don't seem to understand these rules. They truly may not understand they would be losing the right to host someone else that weekend.
I honestly think the problem is people have had a few new tools implemented on them, and aren't using them correctly. If you were booking on a major holiday for example, and someone allows booking on their calendar say a year in advance, then they may not be going through their pricing rigorously on a daily basis, and they may just be canceling because they don't want to give you the place for a "steal", or because they hadn't considered that the place wouldn't be available on that busy weekend. Of course hosts should be more attentive, but many newer hosts just aren't. They are learning the ropes. And to ask someone to lose a week of holiday rates at an East Coast beach or similar seasonal destination would be absolute murder for the owner. There just aren't that many weeks in the destination season.
Have you considered asking what their rate is and offering to book anyway? Or are you specifically looking for a place that is far far below the market rate? I would hope that most hosts would be willing to find some middle ground with you, and I guess you are free to feel as you might, but I feel like it would be reasonable to accept their word that they hadn't updated the price and would you take x amount instead? When you look for a place to stay on a pc, for example, a helpful slider shows up that shows where the bulk of nightly prices fall for the area. I can understand not wanting to be absolutely gouged, but if a host offers a price that is fairly comparable to other places that are similar in quality, I feel like it would be reasonable to accept that price? It sounds like your hosts are admitting their gaffe to you, and then you are refusing to budge. I hope you understand how that would put someone in a bind.
