Michael said:
What did you think was going to be discussed in a TV thread? Only shows you have watched? I think it goes without saying that the entire thread could be a spoiler if you come into it and are not caught up on the shows you watch.
It's still just casual courtesy though. There are lots of shows I don't watch but may want to in the future and it's not like it's a terrible chore to throw in a Spoiler Alert or to make your comments relatively vague(see the above Sons of Anarchy discussion).
Anyways, just my opinion.