Well this is a way to guard your flag in CTF if you just happen to play at Death Island.
However it can only be done at blue base though.
Also in the game there must be tanks and shees available.
http://img132.imageshack.us/my.php?image=haloscreensnapz002se5.jpg
Url above image thingy doesnt work coz i think the image is a bit big (2000 by 1000 pixels)