I've had some exposure to this type of situation, although I'm not sure I have a good solution for you. For field teams, there is generally no need for accessing Mission Manager, and a guest account works great for keeping track of the resource. When guests are helping out with command, it's another story. We have been having someone with access logging in and handing the computer to the guest, or worse yet, sharing their password. Both of these are security issues.
It might be nice to have a button that gives a single user access to a single mission for a set period of time. That would allow a quick way to expand a user's permissions, but setting it up could be awfully difficult. Anyone have better ideas?