So, I bought a 3DS! Turned to be modded with Luma3DS. Returned it.

[OdinHades]

BraLoD said:

It doesn't seem to let me download things to the card, and when trying to do so, it got corrupted, and the system wouldn't even turn on with the card inside, the system would go black, and trying to update the system with the card on, even with no updates available, made it happen as well (as I would restart).

After formating the card it was running well, turning on right, but I'm not feeling well about it.

Do I really have nothing to worry about? It get banned online, or even bricked?

Well, that's certainly weird. Don't know what's going on in your particular case. Could be problems with the SD card, could be a bad hack. But I myself don't have any problems at all. The system works like a breeze, I never got banned or anything. I can play online without problems, I play loads and loads of homebrew and I have a truckload of emulated games on the system. I'm loving it. I only have one single problem and that is that The Binding of Isaac Rebirth doesn't want to update. I don't think that problem is because of my custom firmware though as every other game works fine.