What is the difference between a scissor sweep and a knee sweep?
When I think of the scissor sweep, I think about my shin across my opponent's chest while I pull him/her in and 'scissor' him/her with the sweep. Is the knee sweep just placing your knee in your opponent's sternum instead of the shin across the chest? The scissor sweep seems to lend itself to your opponent sprawling on your legs and having his/her will of passing your guard. The knee sweep, as I believe it, negates that. However, I could be wrong with my theory of what the knee sweep is.
Hmmm...I wasn't familiar with the term "knee sweep". Everyone uses different terms and there are so many techniques that don't have names.
With the 2 sweeps you described, you seem to be concerned with the ability to counter and whether one version was more preferable than another. The bottom line is that every sweep can be countered and be used to pass the guard. Even if you put your knee in my sternum, I can still pass the exact same way as I would the scissor sweep.