Are you sure?
I just was looking at my usual guide source (SchedulesDirect) and they claim Comcast in Chattanooga, TN has WDSIDT2 at 226 which supposedly is Comet.
Unless you mean the other Comcast that came up for the area.
"Comast Battlefield - La Fayette" and also said "Flintstone".
Though Sinclair must make strange deals with cable cos.
In at least two areas that Atlantic Broadband services (Uniontown and Johnstown/Altoona) they never get their .4 channel carried.
Johnstown/Altoona's WJAC has .2 MeTV, .3 Comet, .4 GRIT and Uniontown has WPNT with .2 ASN .3 Comet .4 GetTV.
For months now both Sinclair stations have had a .4 since Comet started back in Oct and the vast majority of cable co's in the area including Comcast never carry Sinclair's .4s.