When I load up the front rack on my all-rounder ( built on a Surly CrossCheck) the steering gets noticeably heavier, but it is very stable, more so than without a load. I'd porteur bikes had low trail, it was most likely tto keep the steering lighter. Load carried ahead of the steering axis increases stability when rolling, but requires some attention to balance at low speeds or when stopped. Just make sure the load can't swing, roll, or slosh. A kid fidgeting is probably not so bad... It is when things move due to dynamic forces that cause trouble.