Pretty much the same story here. We go over the same stuff week after week because most of them are not practicing. After a while, either out of pity or boredom(mine, not so much theirs), I will move them on. It does no good, because now there's just more for them not to practice.
I have this student a month or so back who got into a little scuffle in a parking lot...nothing too serious. He came to class and was telling about it. His exact words were " I didn't even think about using Wing Tsun".
This bonehead has been coming to class (very off and on) since 2005, and he "forgot"?????????
Now if you'll excuse me, I'm going to go bang my head against a wall.......
That's a totally different issue, though there is a relation. Under pressure like a real fight, not sparring, it's normal for the mind to go blank. A person's not likely to "think" about what they're doing until they get a fair amount of exposure and experience to it. What may well happen, if they've practiced diligently, both in class and out of class, is automatic responses that reflect their training. If they've trained diligently, I'd expect a statement along the lines of "this guy got in my face, and I'm not sure what I did, but I pushed his punch out of the way, and then started punching him in the face..." (my poor attempt at describing a parry followed by chain punching...)