Well, for Supercell it is not possible to detect XMOD users. When you are in game activities they are not able to detect you/user. It is difficult for the Supercell to check whether the user is good and just doing the mod in game.
The supercell has a sneaky method to check the XMOD. COC is used to check the notifications of the XMOD. The notifications appear at the top of the screen while the user is playing the game. You need to ban or avoid these notifications by simply turning off the notification mode.
Can Supercell Detect XMOD?
Supercell cannot detect XMOD. The supercell is not able to detect users because it is difficult for the supercell to identify whether the user is good at playing games or simply using a game for a mod purpose.
COC helps to find the XMOD with the help of notification users get on the top while playing games. And to avoid this user can turn off the notification.