Sorry, it's just a pet peeve of mine. The System Menu is no more firmware than the Mii Channel.
When a pet peeve gets in the way of communication, it might be time to re-think it. If I wasn't such a big poster here I likely wouldn't have understood that you were just being pedantic about the phrasing.
Anyway, my point is that they can brick consoles and get away with it.
As other people have stated, it's not just the Wii that does that sort of thing, many devices will lock up when they find they've been tampered with and the users need to send it back to the company who ships it fixed with the latest firmware (it's just usually those checks are removed in the modding process so they don't pose an issue).
However, that's not this situation. Flash carts do not modify the system software.
If they did, then it would be a valid concern. It's a valid concern in the PSP section, I'm adamant about telling users to be careful what firmware they install on which model and to not mess with flash0 themselves...
But I don't feel it's a valid concern
here because there's no system software modification. It's just external devices being used. As stated in the first page, if an external device is mis-detected and the 3DS fucks itself up, that's an issue because it's
likely to happen (hell, one of my friends just today was talking with me about a contact issue between her old DS and pokemon black causing it to freeze) in situations where nothing shady is going on...
But in situations where the internal firmware's checksums (of sorts) are misread, there's two things going on.
1 - The system IS being exploited (not a false positive).
2 - There's hardware damage,
in which case the machine needs to be repaired/replaced by the company anyways.
The main concern with legality is third-party accessories. That includes flash carts. That does not include firmware mods. I've never seen anybody here bitching to Sony about a bricked 3000 (from trying CFW).