Hi Stephen,
Unfortunately, no. Even if we implemented such an option it would be in contradiction with the existing "Save password" option. Anyone who works with Viewer can change any settings in it. Therefore, implementing such a feature would require another user (superadmin) who could define settings/permissions for admin using the Viewer. This leads to unnecessary complication since Viewer is supposed to be used by admins/techs themselves in the first place.
There are other ways to enable stronger security, though. For example, you can enable
two-factor authentication for your Hosts.
Hope that helps.