I see that a lot of people are saying that I'm misrepresenting things.
Firstly, it was pretty obvious that this Riven was either trolling or a bot: She didn't just have a guardian angel. She bought and sold several times to purposefully reduce her gold. I'm confident that at the end of the game, she only had gold for one guardian angel.
Secondly, I don't deny that I rage quit and play bad sometimes. I also purposefully troll sometimes because my teammates have done something mean. But, I have never, not once in my life, started the game trolling, and that's what this riven did. Not a teammate said a word at Riven until she was like 0-5, and I didn't say anything (seriously nothing at all) until this riven was buying and selling her items. What I was thinking in the first place was that she was having a bad game (and I do too I don't deny that) but it was when she started selling and buying that I knew she was trolling on purpose.
Thirdly, some dude posted a game in which I rage quitted. Yes, cool. I should be punished for having that game. My teammates should receive a notification saying "It is at an end trolled, thanks for report, he's been punished". But no, I didn't receive such punishment either.