Any GSMNP ranger is going to throw the rules and reservation system out the window when a situation involving personal safety like this comes up.
I was planning a hike along Hannah Mtn trail in November that included a crossing of Abrams Creek with a 7yo along. When I called up the Rangers to get an idea about current conditions, I was told to set up camp right on the trail if I needed to do so to remain safe if I found the water levels to high for a safe crossing and needed to retreat back up Hannah Mtn... i.e. he was more concerned that I stay safe that I "follow the rules". (BTW... we successfully navigated the crossing with out putting our selves at unreasonable risk... and as a side note, those cold creeks don't seem to feel quite as bad on a cold November day compared to how cold they seem to feel on a warm May afternoon.)