I remember when I was a kid and I really honestly believed it the first couple of times I read a story in which a major comic book character died. There was one time I spent weeks puzzling over why Superman's death (no, not The Death of Superman, another one) hadn't seemed to have caused any repercussions in other comics, and was quite relieved to find everything set right in the second half of the two-parter.
As I read more comics it became apparent that hero death was a regular occurance and not to be taken too seriously. With big-name characters like Batman or Superman it was either a fake out, or at worst an "event" (yes, I do mean The Death of Superman this time). In some ways it felt a bit of a cheat, but I realise now that deep down it was very reassuring to know that however bad things looked, my heroes would always come through, somehow.
It's not like that now. Sure, the iconic name brands are untouchable, but Wonder Woman hasn't been able to hold a supporting cast since before Crisis (the first one), Batman's been largely unreadable for years, and Superman gets retconned so often that I have no idea what Krypton is now supposed to have looked like or whether Kandor is currently only available in bottled form.
And gods help you if you are a B list character. You can vanish from history with a lame explanation, or none at all, and nobody even notices when you are replaced a month later by someone else with the same name. Or you can be built up for a couple of months so that readers will care more when you become the sacrificial goat to make an "event" more... Meanspirited? Depressing? I don't know what the hell the point of that is.
At least once you hit the C list they just use you as dramatic cannon-fodder to show how evil the villains are. Your death may be brutal and violent, but it's usually quick.
So when I read Robin #150 I wasn't excited; I just felt a little nauseous and depressed. It may be, as Kalinara suggests, a misdirection, and Cassandra may yet be saved. But DC already cancelled her comic and they have a new Batwoman all lined up and ready to roll. So I have no deep down tingle of anticipation over how Batgirl is going to get out of this one. No expectation that the clever writer is going to resolve the impossible situation with a surprise twist that I should have seen coming. No faith in DC any more to give me a happy ending.
It's times like this I wonder if maybe I've grown out of comics.