You are right. Random dcs will not be flagged. However. A complete DC from the game server via plug pulling or dashboarding has a specific packet loss pattern. This is easily tracked by the server. We are talking about multiple DCs in the same spot in the raid on the same account. This can easily be flagged. Bungie is notorious for taking action against this type of behavior. See Halo Reach ban (12,000+ people) for more information (same exploit used).

I still don't see how being banned for that is justified, what if someone's power goes out, or they get kicked off Xbox live and it sends them to the dashboard. There is no way for them to know the reason for that happening. I have plenty of friends who constantly get kicked from raids, and strikes, all the way to the dashboard.

Again, muliple time on the same account in the same game space i.e. Crota. The chance of this happening due to randomness is essentially 0%.

It's not at all impossible, it could happen to anyone who might have bad internet(same account) and gets kicked everywhere, including Crota part.