Outstanding and very intriguing idea.
We have now tested this... We used a custom build of Android, dropping all radio features except Wi-Fi. Using a three year old battery, we tossed it up on a bus stop.
43 people downloaded the constitution over three days, zero uploads, a total of 213 connections, over a 67 hour period. Battery finally died, but took seconds to reboot off of a solar panel lock box with magnetic mounts. We’ll leave this up for the next week, should be subjected to two high pressure washes over that time.