New Research: Co-Sleeping Dangerous for All? Or Just for Dummies?

What our setup looked like.
New research just out suggests that Co-Sleeping with young children is dangerous, citing a number of recent deaths. The BBC has the entire skinny here . Some key excerpts:
The risk is greatest if either parent smokes, has been drinking, has taken sedative medication or is “very tired”….
…Data from Dr Marta Cohen, paediatric pathologist at Sheffield Children’s Hospital, showed that of the 50 cases she investigated (of sudden infant deaths) between 2004 and 2007, 31 were found to have been sharing a bed or sofa with a parent.
While it’s no doubt that these deaths are tragedies, all indications are that they could have been avoided if we simplified the rules of co-sleeping down to one rule that all parents follow: Don’t co-sleep if you’re irresponsible, stupid, or both.
Many of these deaths occured when parents were sleeping with children while under the influence of substances like alcohol, overly exhausted, or on sofas. These are all common sense things to be avoiding, and there’s no reason to issue a blanket condemnation of a very beneficial practice like co-sleeping because of a few irresponsible parents.
Then again, don’t feel pressure from parents like me or anyone else. Co-sleeping was a great experience for us with out daughter, but we did it in a way that we were comfortable with, we used a co-sleeper placed next to the bed so it was impossible for either of us to roll over on her. We were still close to our daughter, but we felt more secure about her safety.
Don’t let our culture of fear overwhelm your parenting and what’s best for your child. And don’t pay attention to blankey judgments meant for the lowest common denominators of our society to protect themselves from themselves.

And you know what’s dangerous? How tired my wife and I were before we started co-sleeping. I couldn’t be near sharp objects or heavy machinery for the first 3 months of my oldest daughter’s life.
I wonder what Japan has to say about this study. Co-sleeping is the norm there.