After the bombing, there were lots of grieving civilians looking for "women, children and some men as well". The press had free access to the site as well. His take is that if Saddam had been in the buiding, the site would have been swamped by security forces, and the press and neighborhood residents would not have been allowed in the area.
Secondary thought was that the place (a restaurant) was much to insecure for Saddam to enter to begin with.