I see there is a karma option for oqueue. Great idea but I have now seen how it is abused. I entered a world bosses group and immediately was given negative karma.

I think this is a chance to let people with certain personality issues abuse the system.

If karma is allows is there a way to decay this so that such situations do not create problems for people that raid often?

Your Karma decays one point per day towards 0.

Example 1: 
Today I have 19 Karma.
Tommorow I will have 18.

Example 2:
Today I have -4 karma
Tommorow I will have -3

If I hit 0 karma, it will stop decaying.