Sending Lafet out ahead of them was about they best they could do at giving the Prince warning that they were coming.
"I would like a tour of the important places in the keep, if it is not too difficult to arrange," Lafet said. Food and drink and rest were lovely, but there wasn't quite time for that just yet. "The battlements, the lower gate, where our archers will find best lay of the land. All at your convenience, of course, Your Majesty."