Despite of recent court rulings and delays in implementing the MPAA/RIAA "6 Strike Policy", I've decided to subscribe to a paid VPN/anonymous proxy service.
Comcast is most certainly beholden to content providers, and content providers are the primary source of copywrite 'shakedowns' and infringement violations.
Even if Comcast is unwilling or not required to hand-over the personal information of it's subscribers: I assume this is only the case in a limited number of instances. Overall, Comcast (and other consumer internet providers) will continue to be subservient to its content provider partners requests that they implement an internal copy-write infringement controls.
Shameless plug, the service I used, simply enough, was the first one that came up in Google: Hide my ass (affiliate link...in case you care!), stupid name, sophisticated, and quality service (my personal opinion)!
It's paid: up and running in less than 10 minutes, and the configuration was stupid easy.
I bit the bullet and subscribed for 6 months (probably should have done 12, which would have been a few $ cheaper each month)
It cost: $8.44/month (about the cost of one day's lunch here in Denver)
I'm cheap. Really cheap. $58 up front for 6 months makes me cringe, but a letter demanding $7000 in an infringement shakedown sounds a lot more expensive.