ILGAZ You could have easily missed it since it defaults to ON and carefully buried under "customize" which no OS X user uses. They really know nobody will click Customize and that is why they default to ON rather than OFF.
Another issue with installer is, it "phones home" by needlessly embedding remote images from MS web server in "success" screen. When I got some time, I will sure alert Apple about this potential abuse of Installer/Webkit integration. If we had REAL security experts and non snake oil AV companies, it is their job to alert their customers and Apple about such ABUSE of Installer.app.
(Version 2.3.0.14)