look closely at most airliners which have yet to reach a point in their Aging Acft Program - say 20-25 years - where remedial work and/or re-skinning are required...have seen it regularly on 707, A300, 727 and 747
Most acft have them somewhere - some worse than others depending on utilisation Hours and more usually Cycles/Landings
Depending on design some types appear worse than others because of the light/perspective
Have a look at the B52 at Duxford for an example of real wrinkling of the skin on the ribs!
http://www.!!!!!!!!!!!!!!/open.file/213465/M/