At my studio we have a room just for parents where it is one big window so they can see their child while being separated from them at the same time. This has worked great! But at my studio we want karate to become a family activity, one way we do that is we will have every student go get their parents and bring them out on the floor to help them with a particular kick/punch/self-defense move. This has proven to be very successful as far as teacher-parent relations go.