The inventors themselves may not know. The scenario presumes that the "Singularity inventors" have control of their "invention" and know that it is "the creation of the Singularity". The history of world-changing inventions of the past suggests that no-one will be in control of "the Singularity". No-one at the time will know that that is what it is, and will participate in whatever it looks like according to their own local interests.

Except for all the people on this site, who talk nonstop about deliberately setting off such a thing?