I know reviving old threads is bad form, but a recent change has me desperately wanting this feature:
I've got an "indigo" user auto-logging in and auto-starting Indigo at startup. However, after installing Sierra on my machine, when the system reboots (say, after a power outage) and that user auto-logs-in, the "Please enter your Apple ID" and "Do you want to enable Siri?" dialogs come up. I'm still trying to figure out how to stop that, but in the meanwhile it means that if there's a power failure or for some reason I need to do a restart, I have to be present at the console to dismiss those dialogs before Indigo will start.
Please, please, please move this up on the list of features. Indigo is so very close to being a true client-server setup. I'd really like it to run on my macOS Server machine like any other service.