Thats would be so stupid and overpowered not even gona speak about that being able to climb on walls and glitch inside places and the game is trying to be realistic so nope
First its a game and second no scout would go with a freaking grapling hook while the there is a siege going on with like 200 guards on the walls and archers those things you speak about is a man paid by the sieging army who is inside the walls to go to open the gates even that would be very hard with guards on the walls