Comcast will treat Rokus like CableCARDs, not set-top boxes

The fees come into play if you continue to use the Roku in addition to your Comcast set-top box after the beta trial wraps. At that point, Comcast will treat the Roku device like any other “additional outlet.” That additional outlet incurs a $9.95 fee, minus the bring-your-own-device credit of $2.50 for using a Roku, instead of Comcast’s box. This is also how a secondary outlet that connects to Comcast’s network via a TiVo would be charged and credited.

Basically business as usual.