Evidently the reason some memory leaks from Roger Lamb’s blog didn’t appear in my SPDisposeCheck test have to do with some offending sample code being optimized out when compiled to release mode. When compiling to debug all the offending samples are identified by SPDisposeCheck. Note the differences identified in Reflector.
Screen clipping taken: 3/20/2009, 2:32 PM
Screen clipping taken: 3/20/2009, 2:33 PM
Thanks Matt Ranlett and Paul Andrew for solving the mystery.