Why doesn't Microsoft show the Windows Product Key in System Information?

I personally like Magic Jelly Bean Keyfinder for serial keys of Microsoft and other popular products.

The best I can figure out as to why Microsoft disables this by default is simply to stop casual people copying down the key and trying it on other systems - imagine if you just went to see a demo unit at the shop and re-used their serial key... I know it probably wouldn't work being OEM and tied, however having it a different length just stops any possibility of every day people trying.

With Windows XP, you could activate fresh installations of Windows using that product key 5 times before activation would fail.

If the key was displayed in System Information, a person could walk by your computer, press Windows + Break to bring up the System Information panel, and copy the product key, with no way for you to prevent its future use.

Viewing product keys in any piece of software can usually be looked down upon as a security issue. I'm not aware of any games or pieces of software that will reveal the key used for activation after the fact, and normal users generally do not have multiple product keys in the way you do.

Belarc Advisor will retrieve everything you need. Nice free stuff.