Ubisoft are rolling out a new system to prevent team killing in Rainbow Six Siege with the newest patch. Instead of kicking team killers from the game, it will make them take the damage instead, effectively making griefers kill themselves.
Reverse team killing may be an odd way to deal with griefers as norms would call for kicks and bans of such players, but the issue of accidental friendly fire was too frequent in Rainbow Six Siege, resulting in unnecessary kicks from matches.
Ubisoft came up with a different solution that would still prevent team killing but wouldn't cost players an entire match if they accidentally fragged their teammate.
Reverse Friendly Fire (RFF) will kick griefers in the jewels but it will not punish honest mistakes. RFF will activate if teammates shoot each other, preventing further damage to the target and making the shooter soak up the brunt of it.
RFF will work on most of the explosives from generic or operator-based gadgets as well - most of them will trigger the system in a limited capacity but some exceptions will apply.
Examples from the rule are Kapkan, Hibana and Thermite's gadgets as well as claymores. This is presumably because setting these explosives up is long and their position is obvious enough to avoid them so griefing is virtually impossible. Therefore, these explosives will not trigger RFF.
Unfortunately, other explosives will still deal damage to teammates but this will be changed in Y4S2 as Y4S1 only marked the deployment of the system and further tweaking will be due in the future.
Fuze players will rejoice with the changes as not only will they not get kicked from matches for taking down walls along with half their team inside the next room but they will go unpunished for the moment as the reverse damage doesn't work with the current iteration.
These issues extend to Smoke, Ash and Capitao but are not intended and will be fixed entirely in the future.