A common psychological defense mechanism....projection of blame or blame-shifting, may be one scenario that operates.
So, it is the "snitch's" fault (they are thus to blame), when I get caught violating the rules. This belief allows me to avoid taking responsibility for my own actions.
It also allows the violator to shift the focus from their action (i.e.cross in yard) to the nasty person who has no life and turns violators in.
