From the point of view of copyright, I think this scenario may not have the results you want: the user is effectively preparing a derivative work. In fact, your

From the point of view of copyright, I think this scenario may not have the results you want: the user is effectively preparing a derivative work. In fact, your wrapper is. Preparing a derivative work is an exclusive right of the copyright holder, meaning they can prevent it or place conditions on it. It's not only distribution. Now, no one (afaik) in the free/open software communities will focus on the user here, they may focus on the wrapper/Libbash writer: if the work you're creating is a derivative work, then it is within the scope of copyright of the parts.