There are reasons why drones are not allowed to fly over crowds. This is due to safety because should a drone suddenly lose power, it will crash to the ground and depending on how big it is and whether the rotary blades are still moving, can cause pretty serious accidents as we have seen in the past.
However a company by the name of Indemnis has solved that issue where they have developed a parachute system called the Indemnis Nexus that when attached to drones, would allow them to be legally used in crowds. This is based on new international standards for drone parachute systems which they claim has undergone strenuous testing at at the New York UAS Test Site in Rome, N.Y.
For those unfamiliar, the FAA typically prohibits drones from flying over crowds for the safety reasons we mentioned above. However this is not an absolute ban on drones over crowds as the FAA does allow drone operators to apply for a waiver to that rule as long as they can demonstrate that they have safety mitigations in place, which is what the Indemnis Nexus is hoping to provide to drone users.
The company has since launched it where it will be available for DJI drones like the Inspire 2. They also have plans to expand it compatibility to other DJI drones such as the Matrice 200 series and the Matrice 600 series by the end of the year.