Attack on Anime: Is it already a trend in anime these days to kill a protagonist in the 3rd episode?

I call it a 'trend' because the idea seems to be propagating recently. It all started when they kill Mami-san in Madoka Magica episode 03 but that was the last time I saw something like that happen until Kantai Collection episode 03 arrived. The only difference to me is that Kisaragi (KanColle) is not as likeable as Mami-san but still, I think there's no reason to kill her. Her death didn't change anything, it's as if they killed her only for the sake of seeing her die.

She's not my favorite (because she cares more about how her hair looks than paying attention to dangers around her) but I still remember her as the event reminds me of Mami-san.

The more recent death happens also in episode 03 in the anime Gunslinger Stratos. Similar to Kisaragi, this one character, Shizune Rindou is not as likeable as Mami-san though in latter's case, I can't really blame her. All her actions were due to her being a loyal bodyguard of her master. On top of that she's a loli, at least on the outside (but still have big boobs). If compared to Kisaragi I probably like her more (because of her loli-ness?) but now that she's gone, it's over.

This reminds me of the heartbreaking scenes of killed lolis in Black Bullet.

Then we have Etotama, the original anime not based on a source material. With the main character sporting a Haruhi-like appearance, plus the seemingly happy-fun atmosphere, I thought it would give me another "Nekogami" (the anime) but I was wrong. If I were to pick another anime that gave me similar feeling, it would probably be Mahou Shoujo Taisen, though there was nobody killed in Mahou Shoujo Taisen, albeit the seriousness is quite similar. Regarding the dead character (Uri-tan) she's also not my favorite though I kind of like the way she speaks where she always end her sentences with double '-desu'. Maybe I would like her more if she got more screen time but after what happened in episode 03 now it's no longer possible.

Poor Uri-tan. She received a fatal stab in the head. There's no way she, in her loli body would survive that.

Now my question is who, which character is next? Most of the time I'm OK if one or two character dies as long as it contributes something to the plot, but if it was done only to incite temporary sadness then it's better if the anime maker just keep the character alive. I mean if there's no difference if the character is alive or dead then why bother to kill them?