I just read through the 2011 GSMNP CFR, and it didn't list any expiration date of length of trip maximum for a thru-hiker permit.
SGT Rock
http://hikinghq.net
My 2008 Trail Journal of the BMT/AT
BMT Thru-Hikers' Guide
-----------------------------------------
NO SNIVELING
Just as a note - at least one TrailJournal mentioned taking 10 days thru the park (of course, several of those were zeros waiting for the snow storm to clear up) - it doesn't appear that that poster was questioned, but it would be logical that something like that would be a legitimate reason for taking more than the 7-8 days usually allotted (since the hiker has no control over weather and the park itself was suggesting people get rides with plow drivers - ie leave the trail).
That's inline with the "General Backcountry Permit" rules: $4/night with a maximum of $20 and 7 nights.
The National Park Website for "Appalachian Trail Thru-Hiker Backcountry Permit" https://smokiespermits.nps.gov/index...PermitTypeID=2 says the following:
Thru-Hiker Permit is valid for up to 38 days from the day you obtain it. Thru-Hikers have 8 days to get through the Smokies. A break to rest or resupply in a nearby town does not negate one's standing as a thru-hiker.
There's enough people out there who are fragrantly violating rules (such as taking a dog in the GSMNP back country, camping without a permit, vandalism and destruction of property) that I don't think they are going to be hard @$$#$ with people who are basically trying to follow the rules.
Backpackers that get delayed because of weather or don't want to count "city days" in their 8 day limit just don't compare to these other problems.
SGT Rock
http://hikinghq.net
My 2008 Trail Journal of the BMT/AT
BMT Thru-Hikers' Guide
-----------------------------------------
NO SNIVELING