Oh yes, you're entirely right. I tested with

[SiDMBP2:~] urinine% perl dog.pl
Can't locate feature.pm:   Permission denied at dog.pl line 1.
BEGIN failed--compilation aborted at dog.pl line 1.
[SiDMBP2:~] urinine% sudo perl dog.pl
Hello World
Wednesday
[download]

So it IS permissions. Okay what's the issue:

[SiDMBP2:~] urinine% perl -e 'print(join("\n", @INC))' | xargs ls -ld
ls: /Library/Perl/Updates/5.18.4: Permission denied
ls: /Network/Library/Perl/5.18: No such file or directory
ls: /Network/Library/Perl/5.18/darwin-thread-multi-2level: No such fil
+e or directory
drwxr-xr-x+  55 urinine  staff  1760 Oct 14 14:32 .
drwxr-xr-x   25 root     wheel   800 Oct 14 11:08 /Library/Perl/5.18
drwxr-xr-x   11 root     wheel   352 Oct 14 11:08 /Library/Perl/5.18/d
+arwin-thread-multi-2level
drwxr-xr-x  130 root     wheel  4160 Jul 24 08:26 /System/Library/Perl
+/5.18
drwxr-xr-x   56 root     wheel  1792 Jul 24 08:26 /System/Library/Perl
+/5.18/darwin-thread-multi-2level
drwxr-xr-x  109 root     wheel  3488 Aug 17  2018 /System/Library/Perl
+/Extras/5.18
drwxr-xr-x   72 root     wheel  2304 Sep 21  2018 /System/Library/Perl
+/Extras/5.18/darwin-thread-multi-2level
[download]

So what's in that first directory

[SiDMBP2:/Library/Perl] urinine% sudo ls -l /Library/Perl/Updates/5.18
+.4
total 0
drwx------  3 root  wheel  96 Oct 14 11:03 darwin-thread-multi-2level

[SiDMBP2:/Library/Perl] urinine% sudo ls -l /Library/Perl/Updates/5.18
+.4/darwin-thread-multi-2level
total 16
-rw-------  1 root  wheel  7027 Oct 14 11:08 perllocal.pod
[download]

Yep. Can't access those. So can I pull that out of my @INC somehow, or should I just blast some ugly overblown permissions over the directories?