When I bought my TTA with 1400 miles, the driver's side had a crack on the outside (where most do), as well as on the innner side edge, which I think is less common.
More than a year later with 400 more miles and the car being garaged kept, covered, and pampered to death, the passenger side has now started to crack.
I don't think that driving of the car has anything to do with the forming of these cracks.
I have been able to fill in the crack with a little bondo, smooth it out, then apply the GM touchup paint. Can hardly notice it now. Not a permenant fix, but it does the job until I decide to go with a new replacement.