Some wireless networks are configured to only allow connections for devices with certain MAC addresses, called MAC address allowlisting. MAC address spoofing will cause issues on networks like these. Therefore Tails has a crude mechanism for detecting this, and will show an informative notification about what to do about it.
If you have access to a wireless network that employs MAC address allowlisting, then connect to it with MAC spoofing enabled and verify that Tails shows a notification with the headline: "Network connection blocked?".
