Dags you're right but if he users a starting knot and pulls tension on the top cross properly it will not destroy the string. T ensure the knot does not skip the tail should be held when pulling tension, and I am assuming he is tying a good knot.
When you're dead you don't know you're dead. It's the same way when you're stupid.
Balance - 31.0 cm, Weight - 358 g, SW - 346 Kgcm^2