Comment 19 for bug 893842

command-not-found also needs a fix. From bug 910481 :

To test -
As an admin user run a command for something not installed, the message will be -
To run 'whatever' please ask your administrator to install the package 'whatever'

What should be shown -
The program 'whatever' is currently not installed. You can install it by typing:
sudo apt-get install 'whatever'

confirmed by adding myself back to 'admin' group, then the latter message is shown