Okay, I've never seen a viable master yi support, but I've seen Lee Sin played as support since relic shield came out. It's not a troll pick. It's not meta, but it's viable, and in past seasons was quite common. It was replaced in favor of the tankier melee ad supports, like Trundle and Nautilis, who offer hard cc pre-6.
The problem with reporting someone for playing a "troll support" is that you will always have people reported if someone plays an off-meta support. Which isn't fair to the support players. After the Korean MF support was played recently, lots of people wanted to try it. You'd end up with thousands of people being reported for playing a troll support just for trying something they saw played, if they happened to not do well their first time trying it. All it would take is one person out of the game not knowing about that champion being played globally as a support champ to issue a report. And judging from the number of threads that pop up here every week about "I got X as a support/top/jungle/mid" there are plenty of people who don't keep up with the global picks.
I main support. I don't want anyone telling me who I have to play. I don't mind if the team asks me for more tank/peel/heal/cc. But when they start saying "I don't want you to play that champ, play a real support" it immediately is off-putting. It's not my place to tell any other laner who to play in their lane. Why should they get to tell me who to play in mine?
