You can always mark as sensitive :)…...

You need bigger borders. By the spec there is a "quiet zone" 4 times the width of a single data square.…...

Nothing blocks Nostr clients from sending Nostr events to one another directly, without a relay. Both clients need to be online and show some IP that the other will connect into. Totally feasible. We can even use a Push Notification server to send phone to phone messages with background apps....

It's not up to the base protocol. Nostr only sends signed messages back and for. If people want to create moderated chats, they can use those messages to build any moderation stack needed. NIP-28, for instance, has some moderation capacities that clients may or may not follow....