I just kept my sysnand online with Atmosphere for month now. I used (and still use) checkpoint, JKSV, LiveHex, modified Rom (pknx), sysbot and lots more while on CFW. I also used Home and downloaded games from EShop while on CFW.
So far so good.
I didn't read anyone who has been banned only for lunch CFW on sysnand, you should be safe if you don't install NSP or XCI.
Obviously, don't blame me or anyone else if you will get banned. If you're going to try this, take your responsability