So it's not entirely unsuspected to see abuse on a small level, especially in 3's.
But to address your other point, things like "raging" can happen because people are people, they can have a bad day or a bad game and sometimes they lose their cool.
Win trading takes much more active participation and planning to engage in. It's not a "crime of passion" like some forms of raging can be.
This is why we treat the issues separately.