It seems from I Samuel 16 that Samuel pretended to come in peace, and then anointed David.
Also, if it was done publicly, how come nobody told Saul, look, someone claiming to be prophets is anointing some other guy to be king.
If Samuel did it privately, how did the rest of Israel know that God wants David to be king?
reminds me of Year One quotes:
...that self-same God...
...has promised unto me the whole of this land.
- This is all your land?
For all of eternity.
But apparently God forgot to tell anyone else.
We're at war with someone every other day.