You can only get banned if you use it on the scoring attack. But for safety I use the mod for a day or two, then uninstall it and use the normal apk. Also the yokais I get I don't put in the team until the last week of the event.
It is an excellent MOD, free of BAN except for the scoring attack, but the rest is amazing. I was able to get the ZZZ from the event and I am very happy. Recommended for beginners of the game :D