So here is my story everyweek , we make a group do couple 2-3 chests runs and at some point i join a group lets say +11 / 12 or something and after i use the keystone people leave.
I think blizzard should have a system like to track those mythic plus leavers maybe an icon next to ilvl when we are doing the invites and we will then know those guys are trolling and we wont have to give them an inv in the 1st place.
Edit: I want to point out that people leave sometimes even without any wipes or anything going wrong.