Um. That is my point. Kevin seemed to think so. Look at the pics in the thread.
Venting isn't the issue. The goal is creating some thermal resistance around the tubes so the top plate doesnt just conduct all that heat and act as a giant heat spreader.
My favorite 9018 implementation is audiolab. Westlake figured this chip out. I havent heard anything W4S has done that sounded anywhere close to good. Ymmv of course.