I recently visited the Apple Support page to check the validity of a Serial Number. I was surprised to see that you now have to 'Sign In' to your Apple Account to check your serial number. While this is on the English UK support site, I assume they will have rolled this out to all the other countries.
checkcoverage.apple.com
That will probably put a stop to us generating and checking Serial Numbers for the foreseeable future!
Check Your Service and Support Coverage - Apple Support
Check your Apple warranty status. Enter a serial number to review your eligibility for support and extended coverage.
That will probably put a stop to us generating and checking Serial Numbers for the foreseeable future!