Does the new Fedora package manager allow unauthorized installations?

I would suggest that you try to reproduce this. Most likely, you already had an authenticated session and your system remembered it due to the keyring. A great way to test would be immediately after a reboot.

aditya@20:54:20:~$ nano
bash: nano: command not found...
Install package 'nano' to provide command 'nano'? [N/y] y


 * Waiting in queue... 
 * Loading list of packages.... 
 * Downloading details about the software sources.... 
 * Loading list of packages.... 
 * Waiting in queue... 
 * Waiting for authentication... Failed to install packages: Failed to obtain authentication.

Disclaimer: I am a Fedora user and contributor.