What happened is that author doesn't know how valuable a king is.
A king simple can't go anywhere without an aide or a guard.
Even if undercover.
Now, not only he is without a guard that is supposed to protect and die for him. He also brought along a baggage. Sorry sis, nothing against you. Sure you can read inner voice but so what? You didn't even use it to avoid the arrow.
In short, there should be a guard but romance plot is important now the king gonna have a dramatic moment.