The best answer/question for me would be "should you pre-test" for running/bleeding? I pretest every single batik for running/bleeding. I test regular cottons that are suspect for running and bleeding. As for preshrinking regular cottons .. depends.. on what my expectations for the final result. Flannel.. I would not start a project without preshrinking flannel.
There are so many opinions on this subject .. but I would say that all too often a thread is started .. that someone has had a fabric bleed and are heartbroken and desperate for a cure.