Possibilities are endess, cannot see a use case that could help particulary realise the potential of the idea.
The system would be neutral regarding risks. It would be up to the renter to charge taking into account the risks and/or monitor its use during that time and restore the system to a previous configuration. For the peace of mind of the renter he could rent himself a VPN service and only allow that tunneled internet connection to be used, restrict certain things, etc, etc.
Free market and competition would tend to bring cheap services but the higher thr risk the more you could charge, according a rewarding system of rankings or something like that.
It would be up to each to measure the risks and set things properly, the system would be neutral for that matter and eventually you could make some good bitcoins with it or use it for a specific purpose - like playing a specic stage of a game - and spend some to feed the economies.
Sorry for not going much into spacific cases. I find that a bit vague and don't think would help much the discussion.