> In my view, we should always create a default root if it's needed

I somewhat disagree. I think Serhiy has done a very good job (in what I've reviewed so far) of balancing when a new root should or shouldn't be created (e.g. does it make sense to create a new root when calling `getboolean` as this should only be called once there is a Tcl object to be processed?).

We also have the consideration of backwards compatibility as some weird script may rely upon such errors to, for example, detect when a root has not already been created.