Possibly easily solved by making it easy to lock out (lock-out codes? Or an app with such a toggle?) if a person believes someone else has unauthorized access.

Possibly easily solved by making it easy to lock out (lock-out codes? Or an app with such a toggle?) if a person believes someone else has unauthorized access. The trade-off is an increased risk of inadvertent or malicious denial of service, but properly hardened those can be minimized.