Very interesting question and given the significant rain fall in many parts of our country and hurricane season is right around the corner. I no longer work for a utility so my contribution to your question has to be measured. When I was active within a utility it was SOP to conduct tests on key aspects of our guidelines to first test the validity and also to re-confirm that the original plans are still valid and effective. We were in a earthquake prone area so on a annual basis we did conduct a drill which coordinated Fire and Police into our drill. I can report that after every partial and full test there was never a time that we did not change and refine our guideline.
Hope this help or generates others to provide better guidance then I have provided.