There is no safe way to use an adult seatbelt on a small child. Booster seats don't change that.
Correct, there is no way to use them on a child.
Here's a pic of a boosterseat. This is the kind of seat I would happily provide.
http://ecx.images-amazon.com/images/I/71azAJXR4XL._SL1500_.jpg
You quote Lenore Skenazy, which is understandable, however I'm pretty sure her son was already 8yrs old at the time??
We're talking about 3yr olds. They are not old enough yet to be responsible for their own safety. So it should DEFINITELY
be a priority when considering the means of transport. If the school had provided adequate seating and invited parents to come and
install their seats, then I would say we're talking about balancing the risk of having her in a car with a stranger at the wheel vs the value of the outing,
Just a note, I'm not an over protective or hovering parent. My child climbs jungle gyms all the way to the top without me standing like a jibbering wreck at the bottom saying 'hold tight' 'be careful' 'watch out' etc etc. She uses proper scissors to cut paper and fabric, helps me chop and grate veg using
sharp utensils) etc. and yes she has cut herself, and no I didn't freak out, I talked her through it and showed her how to clean a cut and to put a patch
on. When she paints I cover the entire floor with news paper so that she can paint without worrying about a mess. It makes for easy clean up, and it is
usually necessary to put her in the bath afterwards as there will be paint al over her. So I supervise in such a way that she has the freedom to explore
but I am close had if need be. I like to guide instead of instruct. She needs to experiment and learn for herself else she'll never grow in independence.