Depends, did you do anything hacking related while the account was still connected AND were you online when that happened? If yes, there is a very small possibility they can but they very rarely do account bans unless you were really naught.
Sorry, was totally not my intention. If it makes you feel any better, I'm gonna risk going online with a hack-free EmuNAND to see if its safe. Unfortunately, my console is not 100% hack free but I won't be doing anymore hacks once its online. Also, we don't know if restoring a NAND backup prior to performing any hacks can prevent a ban or not. It just might but it needs to be tested.
Went from dog eating the homework to dogs installing homebrew.