Yes, modern wireless intruder alarms are quite reliable. They use advanced wireless protocols, which significantly reduce the risks of signal interception and hacking. Additionally, these systems come equipped with battery backups that ensure continued operation during power outages, and they often rely on cellular connectivity for redundant internet access, making them highly dependable even if primary power and communication lines are compromised. Regular maintenance, such as replacing batteries when needed and updating firmware, can help mitigate potential issues, ensuring that the system remains effective and reliable over time.