While my condolences go out to the victims and families of the victims of this cowardly attack and i respect the fairplay on both sides of this digital war, i seriously think stopping PB, even for a single day, is a mistake.
The goal of the terrorists is to stop the public life and yes, PvP in NA is a part of the public life. During Portbattles, people from the Netherlands, Belgium, Poland and Germany came together on the Dutch-Nation-TS and tried to work together in a constructive way.
Call that trivial, but for me it is the essence of the european spirit, the proof that the borders and barriers born from the spilled blood of our grandfathers are torn down, that the shadows of the horrible atrocities their generation comitted and endured finally don't hang over our heads anymore.
The barbarians of the IS want to destroy our way of life, our freedom and our friendship. And while they can kill us, our families and our friends, they can't force us to change how we live and what we do. If we change our behaviour we help them in their work.
Don't let them win!
Don't change your way of life, even if it is just a trivial matter in a small computer game.