I've been going through some old videos and found this video.
Every year, we go to great lengths with our customers to emphasize safety when using fireworks. I know sometimes we go overboard and you can sometimes see that glazed look in people's eyes. Most of the time though, people listen and are grateful for the advice we give.
We always get questions about safety distances, "I've got a postage-stamp sized garden, can I let off that 4kg compound?" as you may have guessed the answer would be no. I know that sounds exaggerated, it is slightly but we have had similar questions asked.
The reason a firework has a safety distance can be seen in the video below. This was taken during a firework demo in China some years ago. We got to the test site and the company forgot to bring a launch tube to fit the rocket. The rocket in question was a 160g rocket with a minimum 25m safety distance. So they decided to stick it in the ground and hope it would work. It's dark but you can just make out what's going on.
As you can see, at ground level the burst is huge.
So hopefully this helps explain why safety distances are important and if 1 person sees this and stops them doing something "daft" then it's been worth it.