This video has been out for quite awhile and posted on several sights. In the USA:
FAA considers such attachments on a drone a firearm.
By law the FAA mandates:
A shooting roman candle from a drone can be considered a firearm.
By Federal law, it is illegal.
The law states:
• Requirement for police to obtain a warrant prior to using a UAS for surveillance.
• Specifying that UAS may not be used for voyeurism.
• Prohibitions on using UAS for hunting or fishing, or to interfere with or harass an individual who is hunting or fishing.
• Prohibitions on attaching firearms or similar weapons to UAS.