The article discusses a recent experience of using free WiFi for messaging on British Airways flights, revealing how the airline's system allows access to certain messaging apps while blocking others. It explores the technical aspects of how the WiFi system detects and limits usage based on the domains accessed during the TLS handshake, particularly focusing on the implications of SNI (Server Name Indication) in revealing connected domains. The author experiments with various configurations to understand the underlying mechanisms of the WiFi restrictions.