  It has been shown in \cite{DPSU} that, under some additional assumptions, two
simple domains with the same scattering data are equivalent. We show that the
simplicity of a region can be read from the metric in the boundary and the
scattering data. This lets us extend the results in \cite{DPSU} to regions with
the same scattering data, where only one is known apriori to be simple. We will
then use this results to resolve a local version of a question by Robert
Bryant. That is, we show that a surface of constant curvature can not be
modified in a small region while keeping all the curves of some fixed constant
geodesic curvatures closed.
