Here is the simple refutation of that assertion.

use strict;
use warnings;

use Cwd;
use Test::More tests => 2;

isnt (getcwd, '/etc', 'Not in /etc/');
cmp_ok (-s '/etc/fstab', '>', 0, '-s /etc/fstab is positive');
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The reason is that given by my speedier brethren: namely absolute versus relative paths.