SQL CE Private V. Shared Deployment

I have a couple of questions on the nature of shared and private deployment of SQL Server CE 2005 on mobile devices:

1. I've read that with a shared install, SQL Server 2005 Compact Edition files are automatically updated and serviced by Microsoft Update. I take it that this only applies to installations on desktop computers -- if you're installing on mobile devices, there IS no automatic update. Right?

2. I've also read that in order to do a shared install of SQL Server 2005 CE, the user must have administrative rights. How does this apply to installs on a mobile device? There is no such thing as an administrative user on a mobile device. However, mobile devices CAN require different levels of privilege to install certain programs -- do you need something like an application signed for privileged execution (via a M2M certificate) in order to do a shared install of SQL Server 2005 CE on a mobile device?

Or is the shared versus private deployment only an issue when deploying to a desktop?

Larry