Sometimes people think they are asking a stupid question, but it might actually be quite legitimate and deserving of a reasonable answer.
Kids sometimes ask 'stupid' questions because they do not know any better, or are simply curious about the topic.
No it is NOT stupid to ask a dumb question. You should always be curious and wonder about things. People should not judge you on what you ask because one day you will ask a stupid question then years...
They would ask questions. Since there is no such thing as a stupid question, all they can do is ask a regular question, just like everyone else.