PVS-Studio warning V596 for FlightGear

class sg_throwable : public std::exception { .... };
class sg_exception : public sg_throwable { .... };

void Root::scheduleToUpdate(Install* aInstall)
{
  if (!aInstall) {
    sg_exception("missing argument to scheduleToUpdate");
  }
  ....
}

This suspicious code was found in FlightGear project by PVS-Studio static code analyzer.
Warning message is:
V596 The object was created but it is not being used. The 'throw' keyword could be missing: throw sg_exception(FOO); root.cxx 239

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/