I have always been skeptical of these devices, especially when it has come to light that they have been used in criminal investigations. If I felt I couldn't live without one in future, I'd be inclined to crack it open and install an actual hardware cutoff switch on the microphone. I would not trust the digital microphone cutoff button. I hope that some privacy and security-focused vendor in future comes out with this as an option. Switch on the mic, ask your question, switch off the mic.