Bypass message deletion
If you want to announce something in the channel without actually counting something then you can set up a bypassable role. Anyone with a bypassable role can bypass message deletion by starting their message with !.
You can later edit the message and remove the exclamation mark from the message.
How to set up
You can add a bypassable role with the /bypassroles add command. You can list all your bypassable roles with the /bypassroles list command. You can also remove a bypassable role with the /bypassroles remove command.