but alternative technique is not really a solution. as through the ukes un co operative nature you are forced into bad ettiquette, by not practicing the technique which was demonstrated by the instructor.
One of the understood rules in our dojo is to blend with what is given. If uke is giving the wrong attack for the technique shown and you blend with it and do a different technique sensei seems to feel that you
working on what was shown...blending, you just did it in a different way. I've also found that these types of uke are the first to jump up and say "that's the wrong technique!" To which I reply "not for that attack."