From an article on CNN entitled "Why infants still die of SIDS":
Preliminary research also suggests that babies who begin daycare before 4 months of age, like Jake Haberzettl, may be at increased risk as well. In the most recent AAP analysis, about 20 percent of all SIDS deaths occurred while the baby was in the care of someone other than a parent. One third of the infants died during the first week of childcare, and half those deaths occurred on the very first day.
"It may be that starting a new routine interrupts the baby's sleep cycle, so that when he finally does fall asleep, he sleeps too deeply," says Dr. Moon. It may also be that some providers don't recognize the risks of tummy sleeping.
I know that SIDS deaths are rare enough that their victims are hardly a representative sample of the population, but that strikes me as a weirdly high fraction of first day/first week events.