Anyone can always erase an iOS device with iTunes and recovery mode. That will erase it and break the connection for find my iPhone, so remote tracking will no longer work. Restoring from recovery mode is an essential trouble shooting mechanism and the only means of recovering a disabled device
However, as long as you leave the device listed amongst your devices at your www.icloud.com account, then Activation Lock will prevent anyone from actually using your device.
Find My iPhone Activation Lock - Apple Support
Find my iphone has never been more than a convenience feature to help owners find lost devices. It was never an anti-theft nor anti-crime feature. Activation Lock is Apple’s anti-theft feature.