Crossfire

This would require making a suggestion to update the rules - which you can do in the Suggestions section.

My opinion (Not as staff) - Crossfire is accidental, its not done with the intention of harming teammates - its done with the intention of harming enemies and only enemies. If you are in a situation where your behind someone they are trying to shoot or walk into the line of fire - I don't see why the person shooting should be punished. Bullets go through people, they move or lag occurs - all examples of Crossfire.
 
I don't think we should make a rule over it, staff are expected to be aware that someone shooting a CI didn't mean to shoot the Nu-7 who ran in front of him.

If we put out an official ruling that says "hey you can't shoot teammates but it's ok if it's crossfire" it's gonna lead to more ruleplay than needed. We handle it on a case by case basis regardless, always keeping context in mind.