It is good to take the gains from these exploiters, not to ban them
For many people the rules are what can't be done. There will always be people trying to find exploits and it is only good when exploiters are making exploits public so they can be fixed quick, and the game can be made better.
Right now Anet only care about public or game breaking exploits and noob botters that gets reportet. Pro botters running dungeons and instances are left in peace. Thats the ones who need attention, not a random guy that read about a public exploit.
That wouldnt be very effective in my opinion. Thing is you cannot simply police 24/7 you can to deter people from exploiting altogether. If all you do is take away any gain they make from that exploit you'll end up with everyone exploiting anything they can find thats even remotely exploitable because all they're risking is wasting a little time. On the other hand with a permaban people will at least think twice knowing that this could lead to them lossing access to their game. Not even this seems to be enough really since even though Arenanet already made it clear how serious they were about this lots of people still tried to exploit.