Focal: It's one thing cobbling something together so you can watch free porn on sat TV but being able to hijack the channel and broadcast your own TV programmes is some very different. So yes hackers could get hold of information about where a UAV is and what instructions are being sent to it (which could be used criminally) but actually taking control by sending your own instructions would be a hell of a lot harder. neverless I'm sure someone here will say it's possible.
The insurance question is a difficult one. The CAA's publication tells the world that a UAV must be controlled at all times by a PIC and that the operating company must be correctly licensed to operated commercially. Therefore the liability in the event of a crash rests with them as in the rest of the industry. Of course if it can be proved that the UAV equipment was at fault the insurer could counter claim against the manufacturer, who would then counter claim against equipment supplier etc etc. the counter claim chain could go on forever.
One thing is for sure, if these to ever get airbourne the insurance premium will be high, maybe creating another barrier for operators/developers.