I'm really excited for "Killshot" in two weeks. Kate breaking down, a sniper lurking about it. It looks interesting. As for describing Rick and Kate as "Caskett" I'll repeat myself. I happen to love the shipper aspect of the show and have embraced the fan given title. If someone doesn't want to call them that then don't. Is it silly? Dur. Most shipper given names are silly. Do you want to have fun and enjoy this show? Yes? Then join in with the shippiness!!!
Otherwise feel free to address them as Rick and Kate. Stana and Nathan themselves don't mind the term, I don't see why it is such a big deal other than Christopher doesn't like it.