Passcode are not prompted when using restrictedadmin mode in remote desktop sessions.
e.g mstsc /restrictedadmin
Restricted Admin mode provides a method of interactively logging on to a remote host server without transmitting your credentials to the server. This prevents your credentials from being harvested during the initial connection process if the server has been compromised.
Using this mode with administrator credentials, the remote desktop client attempts to interactively logon to a host that also supports this mode without sending credentials. When the host verifies that the user account connecting to it has administrator rights and supports Restricted Admin mode, the connection succeeds. Otherwise, the connection attempt fails. Restricted Admin mode does not at any point send plain text or other re-usable forms of credentials to remote computers.
More information available from
https://technet.microsoft.com/library/dn283323.aspx#BKMK_Admin