Passcode-secured mobile devices:
Given that a passcode-secured device has had a previous Internet connection and can re-authenticate to a wireless network, you will be able to send commands to it via the Systems Manager dashboard.
If a device cannot get a valid Internet connection because it is locked, then it will have to be reset or restored to factory-default settings.
For example, it has been confirmed that an iOS device cannot be sent a "Clear passcode" command if the passcode has been forgotten and the device itself has been powered off for any period of time, losing its wireless session. This is ultimately because the device cannot complete the authentication process to a wireless network without entering a passcode. Unfortunately, this is a limitation of the manufacturer, even if the device has been previously allowed on a wireless network.