The rules should apply to all game modes.
I'm not a fan of ranked. I had an old account that I forgot the username AND password to, and I tried the ladder. I did my best to climb, and I got decently far. Now I never play ranked. The stress and pressure on me make it less fun, but the thing I disliked most is how others reacted to said stress. So I mostly play other game modes. I play ARAM alot, Dominion is fun, Normals is still weirdly stressful, and I like to rush beginner bots for that nice 150ip every day. I've found fun things to do, and I've learned to play for fun, not elo. Do you want to know whats not fun? 2v5 on ARAM. Once in a while its ok. One of the most fun games I played was a 3v5 on ARAM, but every other game is really annoying. Im fine with 'trolls' as long is its just something like going ad soraka, and not auto pathing to enemy spawn all game. In bots you can go AP lichbane Nashor's Vayne. What is not ok is "We aren't going to report player X, because this is gamemode X (not ranked), and it wouldn't matter."
I've run into so many toxic people, and afk-ers (is that a word?) who don't get reported because of the game mode. If you are on the other team and don't want to report something you cant see ( "He called me a Mother F-----r, plz report"), that's totally up to you. If you don't think what they did was bad enough to warrant a report, that's totally chill. What I think should be made clear, is that the rules of the game apply at all times (Except maybe bots, for trolling. If you report the ad raka in bots, that kinda bm brah). Your D1 Promo has the same rules as my ARAM game full of lv6 accounts. We may be playing different game modes, but we aren't playing different games. While 'Trolling' can be argued against, If you don't report the guy who told my support to kill himself, or report me if I afk bc you stole 1st blood, you aren't enforcing the rules, and you lose your right to complain about those things if they happen to you.