My provider has SD digital channels in the clear plus all HD locals in HD, not through the cable modem, but through any digital tuner with a splitter before the cable modem.
Picture is pretty good for SD.
Just counted, I get 56 digital channels (8 locals in HD) including Longhorn, SEC, my RSN my RSN+ channels, Fox Sports 1, NBC Sports and several others that I do not get on AT120 for no charge with my 50/5 internet and phone service for $70/month.
Of course they could block them at any time, but no so far.