My my, good to know you're a troll / haven't watched R2
Charles Geasses Lelouch and his friends to change their view on reality. Lelouch's memories are returned by C.C. He can't reveal he's regained his memories less he's captured again.
Every time someone has tried to stop him (Rolo, Suzaku, etc.) he has been able to run around them and place someone (be it himself or Sayako) at school while the other one causes havok as Zero
So basically, all the forces of Britannia that already knew Zero = Lelouch know it's happening again, but not a one of them has been able to prove it.