Years ago I used to drive minibuses for a Saturday club for kids with disabilities. We used to meet in a park in Barnes, London. One day we were all out playing on the grass when a bloke turned up with his dog - which was using a wheelchair after an accident left it without working back legs. The kids adored it, and it became a frequent part of the programme.
I'm so glad we were lucky enough not to have that with either of ours. The closest they came was our daughter who wouldn't eat smooth yoghurt. Smooth anything, actually. If it didn't have lumps in it, she'd spit it out, even from four months. She'd just gum along merrily...
Although it sounds like a good idea, I'm not sure it's actually helpful. Look at it this way... Assume at any moment, each child is wearing one pair of shoes. Pass those shoes on when they're too small and you'll still only need one pair of shoes per child, only they'll be cheaper to make and less of an investment lost when they wear out.
Reducing casualties during The Blitz was a bit more involved than hiding out in cellars. A suprisingly effective device was the Morrison Shelter - basically a steel cage you squashed your family into. Saved a lot of lives and even more manglement. Largely forgotten now, it was a useful adjunct to the better known Anderson Shelter. The Air-raid shelter page on Wikipedia is worth a read.
When I had kidney stones, I found that lying down letting the kids jump on my belly shifted small stones wonderfully. The renal specialist thought about it for a while and then agreed that it should work.
http://www.bbc.co.uk/news/uk-england-london-32431623
where the "victim" appears to have ignored reasonable efforts to stop her.
The kids adored it, and it became a frequent part of the programme.
https://www.youtube.com/watch?v=gT9xuXQjxMM
Do you get Father Ted in the US?
Look at it this way...
Assume at any moment, each child is wearing one pair of shoes.
Pass those shoes on when they're too small and you'll still only need one pair of shoes per child, only they'll be cheaper to make and less of an investment lost when they wear out.
The Air-raid shelter page on Wikipedia is worth a read.