less executes a script instead of displays it

### less executes a script instead of displays it ###

support@server:~$ grep ^Ubuntu /etc/motd
Ubuntu 10.04.2 LTS

support@server:~$ which less
/usr/bin/less

support@server:~$ ls -l /usr/bin/less
lrwxrwxrwx 1 root root 9 2011-06-30 10:38 /usr/bin/less -> /bin/less

support@server:~$ file /bin/less
/bin/less: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.15, stripped

support@server:~$ env | grep -i less
LESS= -R
LESSOPEN=| %s

support@server:~$ ls -l /usr/local/bin/test.sh
-rwxr-xr-x 1 root root 23 2011-09-13 09:24 /usr/local/bin/test.sh

support@server:~$ file /usr/local/bin/test.sh
/usr/local/bin/test.sh: Bourne-Again shell script text executable

support@server:~$ cat /usr/local/bin/test.sh
#!/bin/bash

echo TEST

support@server:~$ less /usr/local/bin/test.sh
# this gives...

====================================
TEST
/usr/local/bin/test.sh (END)
====================================

# It runs the script! Fatal warning! :)