I see most people in this thread are forgetting one thing. The 3DS bans happened in a huge waves. First there were the pokemon bans, for anyone who played them online before they actually released. They all got banned at once at some point. Then there was the second wave later that banned a LOT of consoles, which also happened randomly out of nowhere. Back then people basically set on this fact: "Nintendo keeps all the logs and they eventually check them. Once they see suspicious stuff they add it to the ban list to happen during a specific Nintendo Network maintenance".
Second: "But then why people were not banned from 3DS/Wii U CDN downloads?". Simple, 3DS and Wii U had their CDN "open". You could literally download anything from it from anywhere, no authentication needed. Switch is different, when the console makes a CDN request, it attaches it's own certificate, so CDN knows which specific console it is. If that information is missing, then it will throw an error. That's why those two could get banned from it, they downloaded stuff from CDN, which required their console's unique certificate, and it's especially true in ScriesM's case, due to, as he said himself, 'tons of invalid requests'.
