As stated earlier, massplanner gets around 370k visitors a month. Do you really think Instagram doesn't know abot MP or Followliker? It's right on the first page when you search for "Instagram automation".
The only way to prevent Instagram from banning is making a group of like 100 people and hiring a private developer.
I don't know if it's allowed to code such a tool, but if it isn't and Instagram really wants to prevent botting, I see dark times coming for MP.
However, I don't really think it's illegal, otherwise they would've taken down every software a long time ago. I guess Instagress was taken down because they either had financial problems, copyright issues or IG gave them money to stop the software.