It has been reported that consoles do get banned however some users say they got unbanned after a while so that's still a mistery
Pretty sure its around the forum a lot but, there won't be much problems if you just use your ROM backup's header, see every ROM has a different header, if you use your own, only one header is online, but if you download a public ROM, then that header will be online in multiple locations and networks, thus Nintendo will see it, ban the header and the following consoles using the header, so using yours and yours truly is the *best* way to keep yourself from being banned, and with that being said its still unsure, they might still ban you but don't raise the risk, just use your own ROM backups header to prevent being banned.