Allow chat to default to "All panelist and attendees" when chat is available to everyone

During webinar meetings (larger, diverse audiences) we have to regularly tell attendees AND type it in the chat reminding them to change the To: to be "To: All panelists and attendees." The default is "To: All panelists" and most attendees do not pay attention and start typing in chat as if they are communicating with the entire group when it's just panelists. It would be helpful to be able to set this as a default and the attendee could change to all panelists if they don't want everyone to see their comment.