I understand the point you're trying to make.
I've never heard of a child drowning case where the above set of circumstances occurred, though. I've heard of accidental child drownings that occurred because the gate wasn't locked, or when a caregiver wasn't as attentive as they could have been, or when a child wandered off and fell into a neighbor's pool or other body of water such as a pond, lake, etc.
If someone DID do as described in your hypothetical, then I'd say they were a complete idiot to begin with by putting a toddler on a leaky pool float at all, and criminally responsible for a child's death if they left the child unattended on the float and the child drowned under those circumstances.
Regarding vehicular heatstroke deaths in children: It's a fact that sometimes a caregiver has either forgotten a child in a car, left them in the car purposely (expecting they'd only be there for a short period - never a good idea in my opinion), or a child has somehow gained access to a car while playing or whatever.
According to the PSA video that T4Tide posted upthread:
Every 10 days a child dies from vehicular heatstroke in the US.
Since 1998, there have been 575 deaths.
73% of those deaths were children under the age of two.
The above information was compiled by Jan Null, CCM Dept. of Geosciences, San Francisco State University.
http://sfglobe.com/?id=1157&src=share_fb_new_1157
She has also published a fact sheet:
http://ggweather.com/heat/fact_sheet_2006.pdf
This is the first child death in a car due to hyperthermia that I've followed, so I don't know how often or not the caregiver in other cases is charged with a crime, but I do know (based on info posted in these threads) that some cases are determined to be accidental, based on the specific circumstances of those cases.
As we know, in this case, Cobb County investigators & the Cobb County ME determined the manner of death to be homicide rather than accidental, and have charged RH with felony murder and child cruelty. I don't believe RH would have been charged without corroborating evidence to support the charges.
As difficult as it may be to accept that sometimes a caregiver somehow forgets their child in a car - the facts show that it does occur upon occasion.
IMO, based on the currently available information, I don't believe that RH forgot to take his child to daycare as he claims - not in that extremely brief period of time after strapping him into his car seat at the restaurant and arriving at work a few minutes later. I especially don't believe he somehow forgot a verbal 22 month old was in the back seat of the car.
As far as I'm concerned, the known circumstances of this case don't support an accident.
