Of course you need agreement from both side otherwise there is a little bit of being an arse or a bully.
I mean if you know what is coming and you ignore the initial atemi, you can resist almost any technique. Especially if tori is less experienced.
Though I would say this can be quite useful for changing technique because usually resisting a technique in advance will present another one.
Like trying to escape ikkio by removing/ strengthening the arm is going to give you either nikkiom sankio, rokio (provided that you have attacked the elbow as well).
Or someone that tries to escape tenchi nage by break falling before the technique is there will give you his leg to ikkio, nikkio sankio if you see what I mean.
This is my favorite part about sparing. This kind of resistance is not possible. If he ignores the strike to the head, he gets punched in the head.
Of course I agree with you that in static drills it is possible to lock out a partner. Anytime you know what is coming you should be able to defend it. This is where the honesty of giving a good solid attack comes into play. If your attack is committed and the right attack for the drill, the kuzushi and technique should fall into place. I
n my example however, I was referring to someone doing an awful technique. Lets say like you throw a punch, they spin around, take the strike in the kidneys and then tell you that you should be on the ground with a broken hand. (Making up the most insane bad technique I can think of.). Or maybe something more real, they grab your punching hand with both of their hands, then step towards your free hand without taking your balance. Then they pull the arm expecting you to topple over their body into a nice break fall. Assuming this is a black belt, would you stand there with a funny look on your face, throw a fake punch with your free hand, punch them in the face, or take a nice dive over their back into the best breakfall you can muster?
Of course you and I both know that taking the dive is not teaching anyone anything (unless your breakfalls need serious work). Yet by standing there, you defeated his technique. just like escaping that triangle and passing the guard, or using a jab cross to setup a nice hook, or throwing a leg kick to prevent takedowns while trying to get into the clinch.