As both a driver and rider, am adamantly opposed to drivers taking anyone along with them. It is strictly against guidelines & grounds for deactivation.I've seen similar complaints before, and until I became a driver I sided with the complainer.
Now that I see the piddly wages, and know that this is intended to be (or is called) a "Ride Sharing" community. IDGAF and yes if I had a child I would probably bring the child instead of paying a sitter.
As for the legality of it; I do believe the insurance coverage highly discourages this; and I'm sure I've read here that the presence of the additional Pax(child) takes away from the # of seats you contractually indicated you had available for paying Pax.