Children that small should be in the back. It is the workaround for a bad situation (perhaps you have to transport 1 more kid than you back seat can handle and you don't like this one so much). This is also well understood and studied already.
There are commonalities between this and that. But in this situation wouldn't turning off assisted driving in its entirety be better.
Commuter and congested driving conditions by regular drivers assume a pattern of high speed. I do not want my car to have unconditional ability to brake when a computer thinks it should. Period.
Yet... We are now in phases of non-human controlled vehicles and it is a safety requirement to know what outcomes a computer can place on a car going at high speeds.
I would like to be able to create actions that cause my safety to increase against a computer assisted car. If decals (or any actions) make me safer because it makes a computer controlled car behave a certain way, then i will do it.
(my next book: how to defensively drive against self driving cars...hmm. )
If the self driving feature can be completely disabled, that would be much better than just disabling the brakes. Then drive it to someone to fix the assistive driving tech instead of trying to use jerry rigged assistive driving tech.