Never liked insurance companies anyway! They're just put there to give people like me something to moan about. They'll take your money but they always have a list of exclusions which are often the things you're most likely to claim against..
E.g. a couple of years ago my mobile got nicked at work. The council would have nothing to do with employees' personal effects. The trade union would cover you but not for mobiles. I claimed it off my personal insurance but of course that had a ?25 excess.
Now the other day Mrs Mantis has gone and scraped the car (to be fair she's never done it before in umpteen years).
In principle the problem is a bit like yours Smee- we don't get it all back because there's a ?250 excess. So even the car bonnet would have an excess or else the premium would be higher.
Actually, despite what Charles says, eBay are good at sorting you out if the seller defrauds you, though there's a limit on what they will pay. I've done well over 100 deals on eBay and I got ripped off once when the seller had no intention of sending anything, and I used their buyer protection scheme. But even then I should have seen it coming as the guy had zero feedback.