%begin code snippet
logical, optional, intent(in) :: fig
%end code snippet
This code takes the branch for present(fig) = .true. even when no arguments were supplied!
I have verified this using pfg90 v5.2-4 with flags
-g -Mbounds -Mdclchk -Mchkfpstk
on RHEL3.0, Intel Pentium 4/Xeon.