Which is a risk you take as a business owner with a business model that relies on leveraging goods and services. Or you wait 2 weeks for the finance cooling off period (which is there for a reason) and you don’t have these issues.
Are you for real? You can deal with it by having T&Cs that state the customer is liable. Last time I ordered a new car I had to put down a deposit at time of order (when the custom spec factory order goes in), I was clearly told it was non-refundable should I cancel (it was more than £500 as well).
Ling has stated she prefers not to require deposits which is fair enough (I expect it would add to admin costs and would probably scare off some customers, if the web-site hadn’t already 😉 ), sounds a good plan to me to just warn the customer clearly in T&Cs that they will be liable for any costs associated with a cancellation. As long as that is legally enforceable (which it appears to be) then seems to me a better way of dealing with it.
An issue only arises when a customer tries to weasel out of paying those cancellation charges later…