What would people think of "unsigned" events pretending to be somebody else? Sometimes you might not want to be 100% anonymous but also not provably the author. I have ideas on how to make this fancier but the simple approach would be to just claim to be Alice while signing with an ephemeral key. In a public forum this could lead to fun dynamics.
Technically this could be a ["p",<pubkey>,,"author"] tag. This way, the claimed author would get notified and could "ignore the troll" or join the conversation. We could even add a mechanism by which the claimed author could endorse the note in a way the ephemeral author's note would vanish as approved by the author. This could be used by Alice herself when on a device that doesn't have her keys handy, to later click through and approve those messages or when people genuinely think somebody would want to make such a remark.
Of course such a tool could be used by trolls, especially if Alice usually posts using ephemeral keys.
I think, nostr should embrace the strength of signatures in this way - by also providing a way to selectively not sign your messages.
@Vitor Pamplona