[quote="Maresa Sumardi (indomaresa)"]But when an uke is 'wrong' in this aspect, I don't think it really affect the outcome of the technique. The technique is successful, it's just that the uke went splat due to their fault (for a lack of better term).
This can actually result in injury. If uke takes a fall inappropriate to the technique being applied, serious wrenching of joints can occur, particularly if nage has in fact applied the technique correctly. In this situation, I would say that uke was wrong.
One might make the argument that nage has the responsibility to alter the technique, and if nage outranks uke I would probably agree. Realistically, I do not know that this is always possible. There was one situation where I (a new student) applied a kotegaeshi, and uke took a break fall. Unfortunately, I had not applied the technique with sufficient force to warrant a break fall, and uke wrenched his shoulder. I felt awful, but in reviewing the technique with a deshi, it seemed there wasn't really anything I could have done differently.
I agree with Maresa, ukemi is extremely important for this reason, never mind all the others. Injuries, in addition to being no fun, interfere with training in ways that make one sad.