Hapkido,Jujitsu,Aikido,Judo any joint manipulation art should ALWAYS start with strikes,Atemi,softening of the opponent.
The only way a person is going to be able to pull off a joint manipulation move as a first move is if the attacker is smaller,weaker,out of it or the victim is able to throw the technique as a surprise.
I always tell the students when I teach that everyone says in order to use a joint manipulation or a throw you must have a compliant partner.
I say ,I agree,we hurt the opponent to the point that they DO WILLINGLY COMPLY.
The majority of Defenses in Combat Hapkido always have a strike ,a softening at the start of the technique.
In regards to the ICHF Unarmed against the knife ,there are drills to pass the knife ,but they are drills.
The actual techniques are fairly straight forward :
Parry and strike
Catch the limb and strike,then move for manipulation.
One thing that is stressed in actual training with GM P is to strike,and soften the opponent,strike as much as needed.
Striking is not gone into as much on the Video's/DVD's and Books as these are for refresher for current students in ICHF schools,and as general instruction for those looking to learn something from the DVD's.
The Video's,DVD's and Books all state that these are sample techniques,that the student should train at a school or at least attend a seminar in addition to using the DVD's,Books.
Again if training is from Video's and or DVD's and NOT a set school lesson plan,then mix and match techniques as you find they fit your needs.