they remove equipment before taking pictures. also they'll take a white board/paper and they might tilt it and/or just use ingenious lighting to get the effect they want.
Exactly. When you see pics for a contest, don't assume it's exactly how it looks. People will not only take out equipment and add various lighting/back lighting techniques but they also may use fans, remote flashes, etc. In many ways, I feel like some of these contests are more a photography contest but my point is to not assume that these tanks look how they are photographed, be it equipment, effects they use, or getting the right picture at the right time.