How do you guys grade the Overwatch case system?

I'm sorry if this has been asked before, but I haven't seen someone asking for it. Maybe it is dumb question, but how do you grade your review cases?

Like what will trigger positive for you if the player is hacking/scripting or not guilty.

The Feeding/Griefing is very debatable in my opinion which is why I want to see your opinions.

One may feed directly by just walking down mid and one may feed indirectly if they are:

1. Bad players
2. Enemy counter picked
3. Enemy didn't counter picked but played better
4. -||- list may go further

How do you grade this? Guilty, Not Guilty or Insufficient Evidence?

Griefing on the other hand could include more factors as well, which are:

1. Feeding?
2. Not participating in fights?
3. Ability abuse e.g. tiny toss/pudge shard or hook
4. Body blocking with any hero while you trying to go somewhere or just follows you around doing nothing.
5. Buying wards and place them in base or gives them to the enemy
6. -||- list may go further

Again, how do you grade by the most common 'griefing' points under 1 and 2 with question marks?