I understand. I wouldn't add the kids you don't known either. If kids you do know are adding you just to play farmville, but you don't want them to see your posts, one option is to go to the little lock icon under where you write a post, and hit "custom." You'll have the option to hide your posts from specific people--you could put the kids on that list. They won't be able to see what you write, so you won't have to make sure that it always stays appropriate for young eyes. You'll still be able to be their neighbor on farmville
. They won't know you've hidden what you write from them. You can still see their posts, and congratulate them on winning a game or tell them happy birthday. Everybody wins.