EPIRB,
Personally haven't seen/heard of the kids log book concept but yesterday saw a similar concept on Vigin Blue.
They have certificates for "Junior Pilots" for any kid who travels with them and it records their name and flight details. They are more than happy to have all of the cabin crew and flight crew sign it for you as well.
I was a little concerned however that the person receiving it was a 42 year old male passenger tho
He was an aviation enthusiast from a very young age he said..
OzFlight