SHOULD BLACK BELTS ALWAYS BE IN SEPARATE SESSIONS AND CLASSES?

Any dojo/dojang should have a separate class for black-belt-level students, where they can (and are expected to) train to a higher standard. This also helps instructors focus on more advanced concepts and details since the students (again, are expected to) already understand the underlying basics.

On the other hand, I do believe that high-ranking and newer students should also regularly train together. Newer students get the benefit of more individualized instruction, and training new students (even in one-on-one sessions), help black-belts pay attention to their own basics and help them develop the ability to teach/instruct properly.

"always" be separated? No. "sometimes"? Yes. As is mentioned, they serve as role models, and can offer more personalized training. But it can be the case where there are too many black belts, and that can be very intimidating to newer students.

Black belts (actually, any high belt, really) need to be reminded that they were once while belts, so training with junior students should remind them of their duty to expand their art and school by training up the new students.

But high belts do need to focus on their techniques, so it is appropriate to have high-belt-only classes for them.

It's good for a black belt to to be taught in a separate class. And it's good for the lower belts to sometimes train with a black belt. Both have their reasons which have already been explained.

It has been my experience that the black belts do have their own, separate sessions, but they participate in whole dojo classes in order to help the master teach and to serve as role models to those in lesser ranks. Also, a word of praise from a black belt can do a world of good for morale of a struggling younger student.

When our students turn into Black Belts they stay in the same class. I think you should have Black Belts there to challenge the students. Just earlier tonight I grappled two Black Belts in my class and i'm an advanced purple belt.

Black belts should have there own separate lessons, however, they also have to help teach the lower ranked belts.