Until they find out about it and detect the PCIe device by hardware id and ban the cheater.
They even have cheats that connect to the DRAM slots to read character positions from RAM as a wallhack now. Those are still undetectable by anti-cheats, kernel level or otherwise. Only manual review of replays or reports of shooting the wall for half the round might make them suspicious.
Coming out any minute now: https://landing.coolermaster.com/kfconsole/
/s