For Jehovah's Witnesses only please?

The Memorial observance is open to the public, which includes non-Witnesses and disfellowshipped ones. They may sit where they please and are allowed to pass the emblems as well. You don't necessarily need to sit in the back, but usually if people are a bit self-conscious about a situation like that, they will sit there so they can easily and quickly get in and out once it's over.