Ask HN: Does more eyeballs actually result in less bugs?

One of the biggest mantra in the open source world that more eyeballs looking at the problem = better software.

There's another area in life where there is a lot of eyeballs looking at it. Vastly more than any open source software. Those are Hollywood Celebrities.

In theory, by having so many eyeballs look at the life of a celebrity, they can have a better understanding of said celebrity. Yet, celebrates somehow manage to surprise even their most argent followers by doing things unthinkable to them. There is so many eyeballs looking at them yet they all missed a very big "bug" that showed up unexpectedly.

Which takes me back to the open source world of more eyeballs equals less bugs and better software. What do you guys think of this mantra? Does it fulfill all the promises advocates of it make?