We have zero evidence of this, so unless Elf steps up and makes it clear, Magos can countergank all he wants.
Well, Elf told me she'd told Arch (and you, for that matter) to keep away from Lantz, and she told Lantz to keep away from you. So, unless I misunderstood her, yes, it happened. She just did it in private rather than publicly.
Lantz is pretty blatantly setting up a player kill. We have the full right to intervene IC.
Erm, no, if Lantz is setting up a player kill, then the correct thing to do is to let Elf intervene. Just like how the correct thing for Lantz to do when Arch set up a PK for him was to let Elf intervene, not meta-game to avoid it. And, yes, saying "I'll stop you killing x" is meta-gaming, at least as a general statement.
And, for the record, I'm pretty sure he's not setting up a PK, and even if he was intending to I very much doubt that any of your characters could reasonably prevent it (especially without meta-gaming). It's just that Gil is a big part of a lot of Lantz's stories (as a villain, of course), so comes up in the backstory.
