It is important to note that the tragic deaths have been seen with the Infantino Slingrider which is a type of bag sling. Unfortunately bag slings have several significant design flaws that could place an infant at risk of respiratory distress or oxygen deprivation. The babywearing community has known for some time about the dangers of these slings but unfortunately they continue to be marketed and sold. An American paediatric nurse, M'liss Stelzer has documented the results of several studies she has run looking at oxygenation saturation rates of infants placed in bag slings. Her results make for frightening reading; http://babyslingsafety.blogspot.com/
This is a link to the official CSPC report which highlights how important correct positioning is; http://www.cpsc.gov/cpscpub/prerel/prhtml10/10165.html
Also a response from responsible sling and carrier manufacturers because not all slings are equal; http://www.prweb.com/releases/2010/03/prweb3718984.htm
Correct postioning is vitally important when using any baby carrier or sling, anybody interested in babywearing should check out websites such as www.slingguide.co.uk, www.naturalmamas.co.uk and www.thebabywearer.com for help and advice. Pouches, ringslings, wraps, mei tais and soft structured carriers can and are all used by many parents safely and for many years and shouldn't be viewed in the same way as bag slings, after all there are accidents and deaths involving car seats and prams/buggies but nobody suggests they are all unsafe.