I did get shadowbanned from Modern Warfare (2019) for two weeks though. At first I couldn't figure out why my game suddenly would keep crashing on the main menu every time I started it. After a reboot of my PC it stopped crashing, but now the game was taking forever to find a match and when it finally did I got put in a lobby with high ping players from across the world, half of which were obviously cheating.
I managed to figure out that I had HxD (a hex editor) open in the background before I rebooted because I was messing around with the save files of another game. Simply having a process running called "hxd.exe" will cause the game to "crash" and shadowban you for a while. I verified this by renaming notepad to hxd.exe and observing the same thing.