I think it's just a standard message? I currently have a booking made on SQ's website and it does show this:
Please ensure the Assistance & Handling Waiver form has been downloaded to your computer.
Download the Assistance & Handling Waiver form and present it during check-in
Singapore Airlines reserves the right to deny boarding if there is any discrepancy in the information provided, or the relevant forms are not produced at check-in.
But once you click on it, it clearly states that it's for unaccompanied minors between 12 and 18 ONLY.
So don't worry about it....