When a user is working on a git repository and:
1. Clicks the Branch button
2. Types in a branch name that start with "/" (ex: "/users/urig/some-feature")
3. Clicks the Create branch button.
Then he/she is presented with an error message saying:

git -c diff.mnemonicprefix=false -c core.quotepath=false branch /u
fatal: '/u' is not a valid branch name.

My experience has shown that it's hard for novice users to deduce from this error message that removing the "/" will solve their problem.

I would suggest that SourceTree adds a bit of logic before sending the branch name to git that omits the erroneous "/" if it's present. That way the branch is created and the user is spared the error message.

Thanks for considering!
urig