Can I use "can" instead of "could" here?
Generally when talking about possibility, which is what is happening here, while "could" and "can" have similar meanings they do have some different nuance. "Could" is usually used when there is small or weak possibility of something. While "can" is used for general facts or things that have a strong possibility. In this case, saying "a child could make them" is a little weaker and suggests that it's not very likely. Changing that with "can" would remove this nuance. Ex: It can be dangerous to cycle in the city. (Sounds like general fact) Ex: It could be dangerous to cycle in the city. (Sounds like a possibility)