Streaming of "free" TV shows in your web browser from »
xfinitytv.comcast.net/ is available to anyone (you don't even need to be a Comcast customer). You can also do the same thing from the AT&T U-verse site »
uverseonline.att.net/ whether you are a U-verse customer or not.
I don't know about any new official policy that allows getting the basic TV channels without explicitly paying for that service, but I think in many cases Comcast just does not bother to block access to the basic TV channels (local channels and major network channels).