On our Tivo system, we always use the "My Favourites" option when using our EPG to weed out all the greyed out channels we don't subscribe to.
A few months back we were given the "PremierSpt" channel free for a weekend on promotion, so I went into My Favourites and added that channel to my list.
Problem now (seems a bit of a bug ?) is that he channel is in our Favourites list but obviously as the promotion ended, it is now greyed out BUT because it's not a subscribed channel, you cannot remove the channel from the Favourites list with the Thumps Down button.
So now we have an undesireable channel in our Favourites list that we can't remove.