In addition to being able to (through the UI) tell infuse to use "local metadata" -- which actually means local metadata only, ie not augmented by *db -- infuse should find a file that triggers this behavior. eg '.local_metadata_only'. If infuse finds that file, that folder and all children should act as if the user had toggled this feature in the UI. Finding in the filesystem means that I can set this behavior much more easily across disparate folders, and that this feature survives reinstall of infuse and automatic configuration for new infuse devices.
Also, naively it would be sooo easy to implement. It's a no-brainer. There are decisions to make on how to reflect it in the UI. Does a setting appear to 'disable local metadata'? To 'augment local metadata'? Does the same 'local metadata' flag appear when browsing that folder, or a slightly different flag, or a different color text (likely too subtle)? I personally would be happy with a trivial implementation that looks the same as when you set the flag in the UI. If you long press the folder, the popup would look exactly the same. If you disable via UI, you get an error page saying "remove .local_metadata_only' to change the setting for this folder.