If the votes end up being noise, it comes out in the wash. And we already have protections against compelling people to vote one way or another, so carrot-sticking children for votes would (continue to be) a serious crime.
It might even grow our children into a less apathetic public.
I agree, and not a crazy thought. The reasons for voting of the median adult in both parties -- described as charitably as possible -- are suboptimal. The fact that children might be slightly less informed doesn't excuse the disenfranchisement. If anything, children's relative lack of bias might offset their propensity to be less informed.
Our laws and attitude towards "age discrimination" in this country are bizarre and flagrantly hypocritical. The ADEA forbids age discrimination, but only for those 40 or older. This would be analogous to forbidding racial discrimination, but only against some one particular race. Kind of takes away the moral high ground.