Actually, I understand that NOSTR uses the concept of "reaction" and not "like." Therefore, a reaction can be an emoji to show something more than just a like (including a dislike).

Amethyst uses the concept of dislike in a way that is independent of most if not all other apps.

GitHub

reactions should not be used to mark posts as spam/unwanted · Issue #88 · nostrability/nostrability

client initiating action not sure but I think Amethyst, maybe others as well client receiving or observing action (or lack thereof) any what happen...