I did this to the top of the guys skull. Not the back of his neck because it is sparring and I don't want to hurt anyone. I did it as I lowered my center to make it more difficult for him to get my legs. I never kneed them in the face because again, it's sparring and that would be too cruel to do that to your sparring partner.
I don't know everyone's background but some of these guys are bjj guys and Judo guys. I rarely spar against a "wrestler" so to speak outside of the more common place grappling martial arts. A lot of them have a hard time getting a hold on me because I learned how to deal with it, I am not the best at it and I am 100% positive a more experienced person than I will take me to the floor.
But these individuals did not, it worked for me because I guess I see it coming. They make it obvious and normally eat side kick or I just pivot around them. It could be as you said. Maybe they are bad or maybe not as experienced. I was told though to make it as risky as possible for the grappler to get in close, and if he does know what to do about it.
When it does go to the floor I get choked and have no shame in tapping, but not everytime since I been getting better and better at it enough to get back up off the floor. Grappling is really more of a puzzle game, it's a lot of mind games and being several steps ahead which is why I don't like it as much.
I prefer to rely on my strength and relfexes and overall striking technique rather than play a logic game on the floor. I know I am less experienced than you guys here, if I ever come off as sounding like a know it all I do apologize for that. I was just trying to make it clear that I did do it before and the reason why I argue is so I can learn.
I would rather make mistakes here on the forum and be corrected then make them out on the mats or even worse, out on the streets.