Showing the code is not the same as open source. I get that you were joking, but it's a critical distinction. Unless otherwise stated, you should not assume that you have a license to use whatever code you find floating around on the Internet. Public domain is not the default when no licence is specified.
You realize that the source they used wasn't originally released with a license and thus they can't neither legally use the code or release it themselves
If it was released without a license, then in the USA (and all other parties to the Berne Convention), it is automatically copyrighted and all copyrights are reserved by the author.
