As I was putting together the Admin UI, I realized there was no practical way to take advantage of the admin capability to write documents to Sync Gateway bypassing some of the sync function restrictions. This turned out to be a small code fix and now you can sync as admin.
It should be easier to do operational things like syncing the full dataset between two gateways (b/c admin writes don't have to pass the requireUser and requireRole tests). I'm not sure what else it will enable. I just used it to copy all my existing TodoLite data into a localhost Sync Gateway for development purposes. So it can enable all kinds of operational or backend sync patterns, without breaking the security model for application users.
To use this, just point your Couchbase Lite to sync to your Sync Gateway admin port (this port is usually only available to localhost so you might need to set up a tunnel) and you should be able to sync as admin.
Enjoy,
Chris