Você está certo e o artigo da Wikipedia está errado. Veja abaixo um exemplo:
$ ls -l /usr/bin/passwd
-rwsr-xr-x. 1 root root 30768 Feb 22 2012 /usr/bin/passwd
$ sudo cp /usr/bin/passwd /tmp/
$ cd /tmp
$ ls -l passwd
-rwxr-xr-x 1 root root 30768 Dec 21 07:43 passwd
$ sudo chmod 4700 passwd
$ ls -l passwd
-rws------ 1 root root 30768 Dec 21 07:43 passwd
$ ./passwd
bash: ./passwd: Permission denied
$ sudo chmod 4701 passwd
$ ./passwd
Changing password for user vagrant.
Changing password for vagrant.
(current) UNIX password:
$