This is a great idea.
I recently joined up with
www.toysociety.com. I like to make small stuffed dolls and I don't have close by grandchildren at the right age to give the "extras" to so I now make a doll, put it in a plastic zip-lock bag with a "Take me Home, I'm Yours" tag on it and leave it somewhere a young child is likely to find it. (All info is available on the Toy Society website).
It's very fulfilling a lot of fun to do this. There is also the excitement of trying to leave a toy in an open space without anyone seeing. You feel like an undercover agent. Also on the Toy Society site, there are the responses of those who have found the toys and I love to read those as well.
Cheers to All!