But you'd still need to have the build process, so really you'd need submission of the full dev environment. But then you might also need the hardware to run it ...
Personally I think it should be copyright protection or DRM: the demos doesn't get the DRM stuff to enter the public domain so strictly speaking DRM stuff can't be copyright as the deal of time-limited monopoly is broken by the corps that are using DRM.
Submission of complete source code, on the other hand, could help.