Well, there are latches available to secure cabinet doors against a child being able to open them, and if more people who had kids used them, there wouldn't be as much danger. I suppose people tend to keep them there since that puts them in easy reach of where they're going to be used.

If you think about it, the world is a dangerous place. All one can do is minimize the risk of serious injury or death, but one can never completely eliminate it. In some ways, by trying too hard to make things safe, we are making our children more vulnerable later in life, since they will be unprepared for how to cope with the dangers that are present in the real world. Education and proper training will go farther than any lock.