Please don't let this turn into a horrid thread - it's just something me and dp were talking about the other day after reading the threads about Something Special.
I personally think it would be a fantastic thing for children to learn. My Mum's cousin is profoundly deaf due to her mum having chickenpox when she was pg so I grew up knowing the alphabet and have never forgotten it and it's amazing how useful it has been to me ever since.
It's so easy to learn the basics, especially at a young age and would encourage children to learn about and accept children with special/other needs and would probably make the world a nicer place for those who need to use sign language, knowing that they aren't going to be confronted with people looking at them like they're stupid because they can't understand them.