The story goes that someone stole bits 'n' pieces of her handwriting from her book(s) and made it into Susie's Hand. Some people were very anti-Susie's Hand for this reason, and some weren't. I think Ali posted somewhere (CK website or her blog, maybe?) that it was not her official handwriting and not made with her permission, but she was letting people decide for themselves whether they wanted to use it or not.
Then she came out with her official font and now sells all those yummy brushes with her own handwriting at DD.
HTH!