Remove sudo password when connecting to *new* WiFi network
You can edit system configuration files, but that's brute force. First of all, as a rule of thumb, configuration resides under /etc, not /usr or /var or anywhere else. HarlemSquirrel explained how to do a proper change to the default policy.
https://askubuntu.com/questions/244567/remove-sudo-password-when-connecting-to-new-wifi-network