I think it would be cleaner if you had a separate spot for Private notes vs using the "Owners Only" button. We find that we forgot to check this off sometimes notifying the user of a note we do not want them to see or the reverse if the default is checked we forget to uncheck and the user does not get notified of the communication. If you had a field in the Ticket called " Private Notes" and when added gets added to the comments section upon submit and the field cleared would be a cleaner way of handling and you will know for sure that the note is private.