I was wondering, I was going to lend my friend my copy of Super Smash Bros Brawl, but if he plays my disc on his console, will it give him a different friend code than mine? I don't want me and my friend's codes getting mixed up.
Friend codes are just made depending on the Wii, not from the disc.
You can give him your original, a copy of your disc, a copy from the internet. They all will use the same FC once one was created on his console. You won't get the same FC.
This is fact. Just wanted to make this clear as the people before me were just gessing.