Yes, that's correct, if you boot without any other temporary cheatcode.The Cheat-code had to be placed at the line DEFAULT and not at the line APPEND to be effective!
If you want to start Knoppix to try it with an additional cheatcode, you'll run in trouble if there is "nodrm (and/or) nomodeset" not also in the APPEND line of the group "LABEL knoppix".