Bear with me there is a point to my preamble... So in the UK if you buy a train ticket and the train is late and as a result you miss a connection to, say, a ferry then the train company is obliged to put you right. For example, by putting you up in a hotel until you can take the next ferry or finding another way for you to continue your journey so you don't miss the ferry. I once had a free 100 mile taxi journey because the train was late and I was going to miss my connection which would have required an overnight stay.

I am not a lawyer (also this is UK law) but I would be really interested for a lawyer to comment on this, because my understanding is that the reason they do this is because the train timetable is an 'invitation to treat' on which you based your decision to enter into a contract with them by purchasing a ticket to transport you from A to B. If they fail to do this in a timely fashion as advertised on the timetable, such that your journey with them is wasted, this is a breach of contract and contract law says that because they failed to honour the contract, they have to, as close as possible, put you back in the position you were in if you had not entered into the contract with them. They can not get out of this with T&Cs because its a basic principal that if you offer one thing obviously and then say the opposite hidden in the small print, the more prominent offer is what you are held to.

In this case (again, remember I am not a lawyer but on the assumption that the same basic principals were to apply) my theory is that the problem is AirBNB's to resolve because the contract would be between me and AirBNB because the money changed hands between me and AirBNB. So if AirBNB advertised 3 nights in a city for £1500, I paid this and then I arrive and the host cancels my reservation at the last minute, after I have expended considerable time and expense already with the expectation that I have accommodation, I would ignore the host and contact AirBNB directly because I paid them the full cost of the booking and the fact that they subcontracted the actual service to someone else is none of my business, it is ultimately their problem to make sure the contract is honoured by putting me up in another equivalent place or by providing a full refund and paying any additional costs involved in me staying in the closest equivalent place available.

So I wonder, if they don't do this within a reasonable time, could I stay somewhere else and then file small claims court case against them for the cost? If the 1/3rd refund thing from another comment had happened to me I would certainly be tempted to try it to get £1000 + hotel bills back + cost of my time to prepare evidence for the claim at my standard hourly rate.

I have experienced one or two situations where companies have tried to rip me off and taking 30mins to tell them in writing that I will claim, how I will do it, what my grounds for the claim are and how much it will cost them has got them to back down and agree a refund and compensation before I got anywhere near having to fill out the online form for the small claims court, which is apparently not a big deal anyway. No idea if I would have won or how much time and cost is involved though... In general, if people would stick up for their rights more, then the costs of shady business practices like this would make them unprofitable.

Could be a great business idea for an online lawyering startup, like those that exist for flight compensation claims.