From ZDnet:
If Comcast thinks you're downloading copyrighted material, you can be sure it'll let you know. But how it does it has raised questions over user privacy. The cable and media giant has been accused of tapping into unencrypted browser sessions and displaying warnings that accuse the user of infringing copyrighted material -- such as sharing movies or downloading from a file-sharing site.
Jarred Sumner, a San Francisco, Calif.-based developer who published the alert banner's code on his GitHub page, told ZDNet in an email that this could cause major privacy problems. Sumner explained that Comcast injects the code into a user's browser as they are browsing the web, performing a so-called "man-in-the-middle" attack. (Comcast has been known to alert users when they have surpassed their data caps.) This means Comcast intercepts the traffic between a user's computer and their servers, instead of installing software on the user's computer.
A Comcast spokesperson said in an email on Monday that this is "not new," adding that engineers "transparently posted an Internet Engineering Task Force (IETF) white paper about it" as early as 2011, which can be found here.
(Score: 1) by rob_on_earth on Wednesday November 25 2015, @02:27PM
It's not inconcievable that a medical device on a comcast users network would request an unencrypted html page as part of its daily procedures and on seeing this extra code fail in an unexpected manor.
So your first thought in response is that would never happen, but plently of medical and other specialist devices that connect to the internet are 5-10+ years old and before JSON and even before SOAP and XML it was not uncommon to use plain HTML.
I am not saying this is very likely but I expect my packets to be unmolested and most software would agree.