Time travel and sending messages to the past are closely related activities and both don't fit into the established and general accepted theory about time.
To proof a time travel theory, tests have to be conducted to receive back some confirmation of receipt. The objectives of such experiments could be rather complicated and might exist of the following:
The fine line of sending good or bad prophecy to the past might be defined as following:
The idea behind this, is to confirm only that traveling and communication with the past (or future) is possible but in doing so not causing any negative impact on history.
A message should be called bad when the result of an experiment is undesired or the objectives not reached. Sending bad messages can cause collateral damage or the experiment might not generate any result at all.
Undesired results can be listed as follows:
The actual cause of having undesired results might lay with any of the three entities of the communication model. However, it is only the sender that understands what is going on, initiates the experiment and with whom lies the full resposibility for the consequences. The receiver is not aware of an experiment and can't see the impact of his actions on history. He might even think that he is communicating with a spirit of a long dead person.
Since the sender has only limited control over the receiver, he must use the message wisely to influence and manipulate the receiver. The sender might have to deceive, delude and manipulate the seer in such a way that the documents written by the seer are written correctly.
Time travel: how will it look like ?
A message must include instructions on how the reply should be constructed.
A message should be called bad when the result of an experiment is undesired or the objectives not reached.