Buck,

Fair question, and rightly, concernable...

When it comes to using the Live CD, and just BOOTING the Live CD, running the Knoppix OS from the CD, and not "saving" anything to any of your hard drives, it is SAFE.

Using the Knoppix Live CD is about as unsafe as playing a AUDIO CD in your computers CD DRIVE - about as safe as you can get...

When you boot the Knoppix CD, it will create a "memory" resident RAM drive, to store the OS, and any of its configurations, thus, when you shutdown, or reboot, the memory is released and all of its contents are evaporated. When Knoppix boots, all hard drives on the system can be mounted (openned, loaded, etc...) as READ-ONLY, and unless you want to cause problems with your Windows setup, you might want to NOT mount, or view, your Windows hard drives.

When you consider the Knoppix Live CD, booting off the CD, and running "strictly" off the CD, it is about as SAFE as SAFE can be... No virus issues, no worms, no security issues, etc... Since the best any virus could hope for is to get installed into the OS, it can't even get that far, all it would do is attach itself to memory, which, when you reboot, is completely flushed of its contents, it is pretty durn safe.

Code:
DISCLAIMER
This does not mean that if, during the booting, or running of Knoppix that you couldn't have hardware failure, a hard drive crash, a monitor go south, etc... it just means that Knoppix itself won't touch your hard drive installation of any OS, unless you tell it, or ask it to. That is about as safe as you can get.
From what I understand, the Knoppix Live CD was created for someone who just wants to "explore" Linux/GNU, without having to "give" anything up, or add it, etc... to there system. It also is a full blown installable OS, which, if you decide you like it, it can be installed on your hard drive just like Windows. I think the Knoppix CD is the "next generation" of "shareware" - but at the OS level. Try it, you like it, install it. You don't like it, just pull out the CD, and nothing lost in the deal.

But, as far as being safe, I would rather trust "Knoppix" on my system, even the Live CD, before I would trust Windows -=o=- IMHO

Hope this helps,
Cuddles