"Improbable"?
http://www.bhsi.org/playgrou.htm
The Medical Journal of Australia has published a report from four doctors there who examined medical records for reports of children strangled by bicycle helmet straps.
They identified three cases of deaths from hanging between 2001 and 2010:
- a 2-year-old boy who was suspended by his helmet strap between a bunk bed and a wall
- a 3-year-old boy who was suspended by his helmet strap when he tried to climb out of a home window
- a 5-year-old boy who was suspended from an overhead clothesline while jumping on a trampoline
The authors conclude that:
These cases show that accidental hanging is still occurring among young children who wear bicycle helmets while engaging in activities other than bicycle riding.
The reference:
Bicycle helmets and accidental asphyxia in childhood
Roger W Byard, Allan Cala, Donald Ritchey and Noel Woodford
Medical Journal of Australia 2011; 194 (1): 49