[jessaustin]

If the ISP were held responsible by contract, the ISP could either transfer that responsibility as described above or they could just filter their outbound a little harder. The latter solution seems more practical.

[pavel_lishin]

Or they could go the cheap route, and have a whitelist of devices you're allowed to use on your network.

Huh, weird, this whitelist seems to mostly consist of devices the ISP would be glad to rent out to you on a monthly basis...