I honestly don't understand why this is difficult for people to understand. Taking the most treacherous situation: If you fly on both sides simultaneously you just don't do things like resupply yourself from the other side or use your presence on the other side to zero in on enemies and their task groups. If you want to practice shooting at bombers or gvs and provide yourself with yourself as victim fine. Are you unfairly mining perk points? If mining perk points is your objective than yes that is unfair and you shouldn't do it. What is your intent? What are the results of your actions? Does it adversely effect gameplay for other players in a way that is different from the adverse effects that would come from having an additional player that you collaborate with in an ethical manner?
If you feel that someone is getting away with something they shouldn't, tell the office about it. Just because you are not explicitly prohibited from doing something doesn't mean you are allowed to do it.