Putting a copy-protected CD into your Mac may break it, and if it does, it will also void your warranty:
CD audio discs that incorporate copyright protection technologies do not adhere to published Compact Disc standards. Apple designs its CD drives to support media that conforms to such standards. Apple computers are not designed to support copyright protected media that do not conform to such standards. Therefore, any attempt to use non standard discs with Apple CD drives will be considered a misapplication of the product. Under the terms of Apple’s One-Year Limited Warranty, AppleCare Protection Plan, or other AppleCare agreement any misapplication of the product is excluded from Apple’s repair coverage.
(via Interesting People)