Failure to prevent theft
Kevin’s car was stolen shortly after he lost his car and house keys. The insurer turned down his claim, saying he hadn’t taken reasonable care after losing his keys to stop the car being stolen. Kevin disagreed and complained.
Kevin told us he’d had the locks on his house changed but hadn’t got round to changing his car locks at that point. We thought this showed that Kevin realised there was a risk someone might use his lost keys to steal the car.  We decided he hadn’t done enough to stop his car being stolen and so we agreed it was fair for the insurer to use the exclusion to turn down his claim. SOURCE
Keys in an unattended car
Trevor’s car was stolen from his driveway while he was in his house. He’d left the keys in the ignition and the engine running to de-ice the car. When he tried to claim on his insurance policy, the insurer told him they wouldn’t pay as he’d left his car unattended with the keys inside.
We asked for a copy of the statement Trevor made to the police, which he said he’d been upstairs when the car was stolen. The car was some distance away and out of sight, so we thought it was fair for the insurer to say he’d left the car unattended. And looking at the policy documents Trevor had been sent when he bought his policy, the “keys in car” exclusion had been clearly highlighted. We thought the insurer had acted fairly in rejecting his claim.  SOURCE
Theft by deception – really?
A potential buyer for Sarah’s car asked to look under the bonnet while the engine was running and then asked for a test drive. As Sarah was closing the bonnet, the buyer jumped in to the driver’s seat and drove off.  Sarah made a claim on her insurance policy but her insurer declined the claim. 
Sarah’s insurer said her policy didn’t cover theft by deception. However, Sarah hadn’t intended the man to drive off without her. She’d just been closing the bonnet briefly. She hadn’t voluntarily handed over the keys or left the car unattended. So we decided it wasn’t fair for the insurer to apply the exclusion.
In another case, we looked at John’s complaint. He agreed that a potential buyer could test-drive his car. He left the keys with the buyer while he went inside to get the MOT certificate. The buyer then drove off with the car. In this instance, we agreed that John hadn’t taken enough care to prevent his car being stolen and we didn’t uphold his complaint. SOURCE