Of course there's an incentive to not kill them. Most people don't actually enjoy murdering innocent people, and if the police found the dead body then it's a

Of course there's an incentive to not kill them. Most people don't actually enjoy murdering innocent people, and if the police found the dead body then it's a murder investigation which would be taken more seriously than a kidnapping/ransom. All they'd need to do is blindfold the victim and drop them at a random location. It'd be much less risk than disposing of a corpse.