There are 4 ways they can detect a XIM:
- left thumbstick input (WASD)
- R2/L2 input (no gradual change)
- right thumbstick input (no input within the deadzone)
- Sixaxis input (no input at all)
R2/L2 method would be plenty of false positives since you can remap them to digital buttons on a system level on both PS4 and XBO I believe. So if they try something, I hope they try that just to learn the quick lesson of why trying to detect and ban XIM users is a bad idea on a practical level.
I don't know about the gyro thing either. Doesn't that stuff get passed through? I've kind of retired my XIM from PS4 duty. And assuming it's feasible you would get false positives from people using adapters to use their XBO controller on PS4.