I was just precautious, because at that time, even before we could hack it and play online, you always have to wonder what could happen "one day" if you publicly provide your console's serial number to nintendo, or any other members.
if that information alone is enough to ban you for example.
Like you said, all is hypothetical, just preventing any issue and keeping the privacy on a public forum/overal internet information.
For example, if your serial number is used to generate an individual ID, and that ID is used to ban/unban, you could have your console ID banned because someone else used YOUR ID instead of his/her to prevent having their console banned online, and have yours banned instead.
Hypothetically, like I said "we don't know" what it could be used for, always better safe than sorry.
Another example, you posted your full serial ID. Nintendo knows you did, and that serial is linked to you (as a member). So far they don't care. But maybe they have access to that serial ID when you play online, or access eshop, still they don't care you do, you did nothing wrong.
Another day, years later, you come here and tell you dumped a game (say ... the next Super Mario, before the official release date) and provided it online, you are happy ! you did something first before anyone else dumped the game, you want to share your exploit.
Nintendo probably has your billing address linked to your serial if you ever paid something on their eshop. they have a way to trace you back to your real identity and arrest you.
and ... OH YES, it already happened here, on this forum, in Wii section !!
don't doubt Nintendo will do what they can to protect their IP (Intellectual Properties) by all means necessary.