When lighting a bag on fire what could go wrong? Surprisingly, Sky Lanterns are very safe. There's a whole festival for Sky Lanterns in Taiwan each year. It's a pretty romantic thing to do when the mood strikes you.
Implications - The featured video shows these glowing Sky Lanterns getting sent up into the air and filling the night sky with a beautiful glow. The Sky Lanterns are made out of flame-resistant bags so that they won't be able to start a fire. Some people write messages on the lanterns before they are sent up into the air and out of sight. It certainly would be something amazing to see in person!