I don't take my wife - too dangerous to have both of us on a single bike. I do take my daughter who is 11. She has all the gear - easier to get kids gear here in europe.
Anyway - while it is of course dangerous, at 11 and with an intercom, it is great. What she (and i) get out of it is definitely worth the risk (easy to say right now). But i has been a big benefit to our relationship.
Conversely, she fell off her ripstick the other day and hit her head on the ground - got a concussion. Scary.
Me: You should think before you speak.
Daughter: That always backfires on me.