Agreed but why would the person buy something he already has
It actually completely different person B is not going to resell the plans
Using your CD example
It like a Musician buying the CD and learning to play the song/s on it to play in Public
This actually comes under performing rights and it depends on who wrote the song in the first place (I worked in the entertainment industry for 15 years)
So how does one Licence something like a MINI MAX or an aircraft build from plans downloaded form CFair yahoo group etc
Then there's the problem with the CRI CRI and who actually owns the rights to the plans