Ranked Restrictions used to be a form of punishment, often coupled with Chat Restrictions, that forced players subjected to them to win games in the Draft Pick mode.
This is no longer part of the Tribunal’s set of punishments.
Ranked Restrictions were intended as a punishment for moderate toxicity and negativity. [170, 224, 295] There were also plans (albeit at low priority of development) to implement them for leavers. 
While misbehaving ranked players were the intended targets for the restrictions, players that were deemed to be at risk of being more toxic in ranked games than normal games could be restricted in their ability to join Ranked queue too. 
Ranked Restrictions were planned to be included in the report feedback feature, with some caution from Riot’s part due to the possibility that the notifications would be too spammy [58, 127, 374], but the plan got cancelled with the retirement of this form of punishment. In fact, as any other punishment system, reports were used to identify misbehaving players and hit them with Chat or Ranked Restrictions where appropriate. 
However, contrary to popular belief, Ranked Restrictions weren’t handed out for a single game only, but as a result of a pattern of bad behaviour that the system picked up on. 
After the implementation for Reform Cards, they were supposed to show the match history of the games that led the player to get restricted from Ranked queue. 
The only way to get rid of Ranked Restrictions was winning games in Draft Pick. This choice was made on purpose, so as to force players to play the game, instead of going AFK or troll for the purpose of getting rid of their allotted restrictions faster. 
As per any other form of punishment, during the development stage of the report feedback feature Ranked Restrictions were supposed to be included in it, with the feedback pop-up only appearing to the player whose report triggered the punishment. It was set this way in order to avoid spamming players with too many notifications, since about 20% of the surveyed players was not interested in seeing them. [364, 374]
In August 2015, Chat and Ranked Restrictions were wiped from players’ histories due to the upgrade to the Instant Feedback System , which also signaled the retirement of Ranked Restrictions from the set of punishments.
Due to human bias, it may have seemed that Ranked restricted players numbers are very high, but they’re actually much less than players with ribbons. 
Fewer than 1% of players have received any form of punishment. [189, 198] Adding to this, according to statistics from 2014, 95% of active players have never received a punishment of any kind. [190, 198, 199]
According to 2015 data, since introducing ranked restrictions, verbal harassment reports in ranked games dropped 18%, and after identifying some of the motivations behind ranked play and designing a system that provides meaningful penalties related to those motivations, the percentage of ranked games with moderate negativity fell 28%, and the percentage of ranked games with high levels of negativity (such as death threats, sexism, racism or homophobia) plummeted 47% to 0.8% of all ranked games. [213, 214]
Ranked Restrictions were criticized as a softer form of “prisoner’s island”, but Lyte stated the majority of Draft Pick players were neutral or positive (while about 1% of players were afflicted by Ranked Restrictions ), and the intention behind forcing ranked restricted players into Draft Pick was to surround them with positive examples, that they could take inspiration from to reform. [218, 219]
127 https://ask.fm/RiotLyte/answers/130577014978 ; Page 322
170 https://ask.fm/RiotLyte/answers/130580680386 ; Page 319
287 https://ask.fm/RiotLyte/answers/134278773954 ; Page 21
307 https://ask.fm/RiotLyte/answers/130600611266 ; Page 310
364 https://ask.fm/RiotLyte/answers/132088444610 ; Page 133
374 https://ask.fm/RiotLyte/answers/131060874178 ; Page 207
459 https://ask.fm/RiotLyte/answers/132459485122 ; Page 103