If you accept a 0-confirmation transaction and listen the network for a few seconds to ensure no double-spending transactions are broadcast, this is a reasonabl

If you accept a 0-confirmation transaction and listen the network for a few seconds to ensure no double-spending transactions are broadcast, this is a reasonably secure way to accept those small transactions where 10-minute delay between blocks (resulting in a 5-minute average wait) would be a problem. Of course, you'd still better wait for 6 confirmations if selling a car.