Ubisoft released a dev blog talking about the Rainbow Six Siege reputation system that is already running but the players can't and won't see for a while.
Just like the name suggests, R6 Siege's reputation system is another tool that will try to reinforce positive behaviour and minimise the negative. The idea is fairly simple in the sense that things like these have been done in other competitive games before, with Overwatch and League of Legends coming to mind first.
Overwatch has the Endorsement while League features the Honour system. Each of these systems gain levels as you are commended by the teammates and go down when you are reported or exhibiting other negative behaviour such as going AFK or griefing. Similarly, R6 Siege reputation will have five levels, ranging from zero to four.
Zero and one will mark the players as having negative standing, two will be reserved for those with neutral standing while three and four will be seen as positive standings.
The dev team implemented this team and has been observing player behaviour in order to work out the kinks and introduce the system when it's properly ready. Speaking of which, it was initially planned for release with Operation Neon Dawn but was pushed back and will probably launch officially during Year 6.
It's preventive sanctions that will come out first but the team will keep reiterating to bring the best possible front end experience during the year. You can check out more details on the reputation system on the official blog post.