File Sync and offline access

Here's another thought: why don't any of these tools run as a service? Most of them either die horribly or don't run at all (without reinstalling) if I log on as a different user or switch to another user without logging out from the first user account.

I'm thinking along the lines of Windows File Replication Service....runs all the time, in the background, low impact, completely silent. Only time I need to see something is in the event log or when I open a management tool. Or something that runs/triggers from the Windows Task Manager. No need to keep these apps open all the time unless they are doing live file difference/change monitoring. And even then, running as a service makes more sense than running in my current user context.