First - Think of something involved in acquiring real property - a house for instance - and what could go wrong that the buyer might not find out about until after the purchase is over and has moved in. (Don't use "title" problems as an example). Second, think of an insurance product that someone might be able to sell that would cover that problem; but that might not occur with predictability (for instance, an insurance policy tocover the payment of annual property taxes would be silly, since everyone knows when and how much they'll have to pay for property taxes).