Eshshshss
That take seems a bit disingenuous.
1 / 4 - Not sure how you arrived at the conclusion that a random person doing the same thing is not ok from this mention. The idea here is that if you're taking actions to intentionally stay in those lower ranks, regardless of whether you're a streamer or not, that will be actionable. As a side note to this, if you're greatly outperforming in those earlier matches, you may notice matchmaking is taking that into account and getting you out of those lobbies faster and in fewer matches - smurfing or otherwise.
2 - Are you intentionally doing this? Not fine. This behavior is investigated by a team manually. It's really not as simple as, "Oh it was a different player that match, totally not boosting 😉😏"
3 - If you have reason to believe it's a smurf or hacker, please feel free to report them. Any penalties from disconnecting are going to be the same regardless of the reasoning behind it. There's not a way to infer your intentions when you disconnect from a match.
It sounds like you may be hinting at some sort of system that would reimburse your RP/remove the penalty if a player on your squad was found to be cheating, which is a point of feedback I've definitely seen pop-up before. That's certainly feedback we can continue to pass along, but as that's not currently how things work, a disconnect is a disconnect.