The only Person with the power to control the fallen angels is Jesus Christ and if a person chooses not to accept Him as Savior, then they are vulnerable to anything happening to them and they have no way to defend themselves and no protection.
That said, there are many people wobbling at the Crossroads...and Satan is working on them feverishly (just as God stands stalwart like a Rock, ready to open the doors of Salvation to those who will accept Him).
But ultimately, acceptance of evil goes hand-in-hand with the rejection of God.
The one thing I have noticed about the successful exorcisms I have read about and heard about is that the possessed is, by the process of the rite itself (and by the Power of the Name of Jesus), taken back by God (but that too requires a decision, an agreement, on the part of the possessed).
As we all know well, acceptance of our Savior does not stop Satan from pouring on the temptation.
And I have seen some people I thought were so incredible lost they could never be saved miraculously turn to Jesus when they hit bottom.