well the fact that we all were so optimistic about Gum Drops was that Grissom was in the Promo... and that someone had told us that he had finished filming his scenes before leaving...
Oh! That's right - I forgot about that.
They did the same thing with The Unusual Suspect and Hollywood Brass. I imagine they know that their fanbase is somewhat pro-Grissom. lol.
Which is why they're trying to make this upcoming episode look so important. Like he's leaving forever. Because if the ratings go way up for this, they may be able to cover the Grissom-free episodes for the yearly total. And again, it's nice to see that they're using GSR as a plug for that big milestone.