To test the theory, do a render with the Diffuse_value of the box shader set to zero. The reflections should be as strong on the front side of the box as on the rear - stronger, in fact, since the floor is more brightly lit in the foreground.

Izi

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)