I've mostly been allowing users from within the game or rcon and so it writes out the allowlist.json file. I've then backed up the file so I can restore it when it disappears again. Restoring sometimes fails and that may be because I need to stop the container first -- I'll try that next.
Yes, I suspect this is the case but I have not tested it since I have a backup plugin that restarts the containers weekly. On restart it would automatically update.
Thanks! I'll give it a try.