A Swarm of Nano Quadrotors

You are postulating a group that is willing to hijack an unmanned truck in order to steal the goods being delivered and doesn't mind the risk of being seen because they "have a bandana and shades on". Question: What is so special about an unmanned truck given that circumstance? Wouldn't it be at least as easy for a group like that to hijack a manned truck? Why don't the same gangs pull a gun on the UPS guy and take all his stuff? That would be in some ways easier than taking stuff from an unmanned delivery van. The unmanned van can go into lockdown mode and doesn't have a driver who can be threatened to make him give up the key to the back. The cost for any private party to send up their own monitor drones is coming down very quickly and will likely be insignificant by the time unmanned delivery vehicles are common. If one unmanned delivery car sends out a distress signal, other unmanned delivery cars in the area could release drones monitored by a local security firm to go see what's happening, follow the bad guys, and tell the cops exactly where they went. The sort of drones I'm talking about might look like this: [this video] (You can already get copters of that sort with at least a 10 minute battery range for a mere few hundred bucks.)