Objective-C 2.0 Garbage Collection, Part II
It turns out I was wrong (it will not be the last time) about the four apps I pegged as possibly using GC in 10.5 here.
Mark Rowe (engineer at Apple) posted a comment to my original post with what appears to be the definitive mechanism to determine if an app is using GC.
I spent some time digging around in otool before moving on to my (incorrect) heuristic of looking for certain imported symbols via nm.
I am happy to stand corrected. Thanks Mark.