Buying a 3DS with digital games installed.

I think it's a little too risky. You'll need access to their Nintendo Network (assuming they made one; if they didn't, then I'm not entirely sure of how digital game transfers work).

Don't buy a preowned 3DS! I have one and you should only buy one if you can get an extended warranty. The hinge probably will crack.

Bump!

Edit: I found the option to erase your Nintendo Network ID (it was kinda hidden) and it says you won't be able to use or download those programs anymore. I guess he will have to use the same ID if she gives him her password. What about unlinking that ID from her Nintendo Club account? It seems that there's no problem about doing that.

If the seller gives him the password for the Nintendo Network ID that is associated with the games it's no Problem.
But your friend have to use this ID including the Nickname of the preowner to play that games. He can't use his own ID or delete the previous ID without deleting the games.

Edit: He just have to go to the e-shop and unlink the Club Nintendo Account and can than enter his own one.

The games will be installed into the SD memory card, he can just remove that card and use another card for his own nintendo network ID.
But if he makes another ID in the card that has the games installed, he won't be able to play them.