Yes, the headline is misleading. It says the children were “locked up” as if they were in a dungeon, but in reality it was their home and the whole family was living there.
Link to the story with photos: https://www.google.com/amp/www.foxnews.com/us/2018/03/01/california-family-found-living-in-box-for-4-years-officials-say.amp.html
The question is whether they ever let the children out.
So apparently the two parents were basically arrested for being poor and trying to subsist without being wards of the state ...