It's really about common sense and responsibility. If I were going to make some thermite or something, I'd do a bit of research to see what safety precautions to take. I'd keep a good distance between myself and the thermite, and I'd make sure that everyone else was also a good distance away. I'd make sure nothing of value was near the thermite, and I'd make sure I could ignite it without being too close.
When something is dangerous, you have to approach it with caution. Specific knowledge (like "grounding in pyrotechnics and demolitions") lets you know how many liberties you can get away with, but in general, you just have to be cautious. Sometimes cautious is "don't do it at all", but only rarely.
A small bomb in a dirt field with nobody around doesn't really do anything dangerous. A mega-bomb in your basement does. You don't have to know much about pyrotechnics to know this, you just have to have some common sense.
Watch Mythbusters, they do it right every time. Start with small scale, if it seems to work, try a bigger version. That applies to everything.