I did this some years ago. My 2 kids both ordered child skillets and DH and I split a steak.
My DD ended up eating half my dinner. So I took 2of her ribs (we mentioned this laughingly to our server). When my kids asked for refills, the server brought some extra and put it on DH's plate to "hold for the kids". He ate them. We both ate the sides my picky kids wouldn't touch (but specifically did not ask for refills for these).
Our server was very good with how he handled this.