Actually, you can make this rather difficult for the hypothetical 12 year old with a hex editor.
You can incorporate hidden codes into places where they don't look like hidden codes, for example low significant bits in an included image resource.
Secondly, you can incorporate a multiplicity of codes in such a way that you would need to own not 2 copies but a great many copies in order to find all the codes. Each issue would have some codes in common, but others not in common.
You have to do something sophisticated, if you think like a 12 year old then you can expect it to be cracked by a 12 year old.
But what about passwords for downloads? That's no problem for us legitimate users, and a cracker can't guess an 8 character password.
Presumably Fred doesn't think it's worth the effort.