Research into how to build a powerful AI is probably best not done in public

I find this dubious - has this belief been explored in public on this site?

If AI research is completely open and public, then more minds and computational resources will be available to analyze safety. In addition, in the event that a design actually does work, it is far less likely to have any significant first mover advantage.

Making SIAI's research public and open also appears to be nearly mandatory for proving progress and joining the larger scientific community.