One concern which doesn't seem to have come up is corruption of the games.
I had a game on my DS, had fun playing it, up until one day the data on the cartridge corrupted itself in the middle of a game. No warning, just one moment playing, the next minute everything froze.
Reset the console, game started loading up, got to the main menu screen and the sound was just a screeching mess, and the graphics severely scrambled. Tried it on a friends DS, he got the same result, all other games worked fine. I concluded that somethign happened to the memory, got annoyed, got over it, and bought another copy of the game.
But, what if this happens on the 3DS? Can that be accidentally construed as hacking? It's an "operation" outside the normal realm for both console and game. How will the monitoring software interpret such an event?
Also, what does this mean for after market peripherals? Devices like the Gameshark have been around since the Super Nintendo. Does that mean that if someone uses a device like that their console gets bricked as well?
And finally, you can frequently find DS game cartridges like this
http://cgi.ebay.com.au/POKEMON-WHITE-NINTENDO-DS-DSi-XL-w-ALL-649-Lv100-SHINY-/250782091068?pt=Video_Games_Games&hash=item3a63c7073c
and this
http://multidsgames.com/store/product_info.php?products_id=83&osCsid=doi854b20cs8g7ai1phd1aso25
Neither of these products are set up the way they came from the factory. While I would never consider buying them, not everyone is going to feel the same way. Especially those who know very little about the console or the games.
I can see a parent buying one of the multi cartridges for their kid because of the apparent savings on offer for them, and I can see such Nintendo bricking the console, because it is not a legitimate Nintendo product.