Devices like this rely in part on the hawthorne effect. If someone thinks they are being monitored and because they want their $100 deposit back a vast majority will comply.
Also consider the penalty threshold and probability of being caught for the two acts. Flipping your wag bag down one of the backside main trail windows with no one watching is almost a zero risk and only a fine if caught. Taking your ice axe to a national park service device with cameras and in the portal with people sometimes around is potentially a federal offense and is a much more risk adverse behavior
You would have multiple readers if one failed. In the unlikely event of a total system crash refunds could be credited for those who requested them during that time period.
Unmanned reader technology devices and their security and monitoring have been vetted for decades.
There are half a million atm machines in the us and all the comparable barriers are managed. Managing an unmanned atm device is way more complex than a terd bag device.
