RebYidd23:
All the cubicles I have seen in shuls have numbers and keys. I’m no locksmith, but how do expect the phones to be stolen? The location might not be a central area, but it is certainly not private and without traffic. Who would be picking at a lock to find a phone of questionable value? What’s the risk of being stolen?
On airplane mode, the phone can vibrate in your pocket. If the goal is that the phone not disturb anyone, this vibration in the pocket makes that goal unattainable. Why is that preferred? Are you a doctor on call?