Group 1 - A passenger on Xiamen Airlines flight MF8318 experienced a "free downgrade" from business class to economy class due to weather-related aircraft adjustments [1] - Xiamen Airlines stated that such downgrades are not uncommon and can occur due to factors like weather, air traffic control, or aircraft malfunctions [1] - The airline offers passengers the option to change their flight, switch to a different class, or receive a full refund if they are downgraded [1] Group 2 - On May 6, Shenzhen Airport activated a large-scale flight delay emergency response due to thunderstorms and heavy rain, with delays resolved by the morning of May 7 [2] - Meteorological forecasts indicate that Guangdong will experience heavy rain and strong winds from May 9 to 10, raising risks of flooding and geological disasters [2] - The Guangdong Provincial Flood Control and Drought Relief Headquarters initiated a level four emergency response for flood prevention on May 8 [2]