When importing a single secret key, you are asked if this is your own key, to decide if the owner trust is set to ultimate or not.
This question may confuse people if they import a shared key (which is done for reading encrypted mail to functional mail addresses).

If people answer "No", as they should, they may wonder what to do with this certificate in order to use it, as it is now marked "not certified". The answer would be that they need to certify it with their own key.

To lead the user to the solution we could open a certification window next, as we do when importing a single public key (if the person has their own secret key, that is).