I absolutely agree. I'd push it further though. Not just children but anyone who is not in a capacity to freely spend the money. To make a contrived example, someone may not simply kidnap a person and take their universal basic income.
I go farther to say that local/state/federal government may not take the money for people in their custody. There ought to be some way to protect it from being garnished as well.
I think we should not oversell this. There might be a lot of people who are perfectly content with being able to survive and get by. If they do not want to participate further in the economy, I think we should say that's fine. The ax I have to grind in this is that maybe if people are not scared of starving to death after leaving a job they don't like doing, maybe we will have more people doing jobs they do like doing and maybe just maybe me and others will have a better shot at doing what we love doing even if it is at a slightly lower (after taxes) pay than before.