Some martial skill sets. Compliant ukes help considerably with others, though.
Language is always difficult. Cooperation is not the same as compliance IMO.
It's really a whole new thread.
Let's say we want our uke to be compliant. Compliant with what? Falling down and 'respecting my ki'? Making it difficult for me to achieve a technique?
Our training goals together, or yakusoku are what we should both be "compliant" with. That should include honest feedback. One (among many) reasonable agreements should be, "if I can do it, I should" with in the rest of the agreed upon ruleset.
I don't think falling down out of respect, or because I'm afraid I'll be sandbagged and then scolded for not respecting someone's ki is a good way for me to practice. A good partner can put me down without hurting me.