if you are very serious about protecting certain groups from seeing certain words or topics in the chat, a warning is fair enough, but because the chat moves so slowly when there is not a lot of people online, that 'inappropriate' message or words can hang around for a long time with many people still able to view it. apparently staff are unable to delete the messages.
cons of the idea:
staff abusing the delete function to silence people they don't like, or cover up stuff they have been talking about with users in the chat logs
any way to delete the message in the chat but keep it in the logs?