In our dojo, practice beyond the most basic beginning level is always from random attacks, so students never know what kind of attack will be coming from their partner. Since rejecting the technique emulation model and adapting a model that stresses an understanding of the spiritual nature of attack, I have seen my beginning and intermediate students perform aikido at dan levels from unprescribed attacks - including demonstrating classic aikido forms they were never taught or even shown. That is not to say that there are never any attempts by students to use the physical force or leverage advantages provided by body mechanics that come into play during an aiki interchange, but those attempts are quickly seen to be futile in attaining the ideal expressed by the Founder.