Autonomous software is a lot more complex than the software the ECU uses (which is still complex), so there may be a genuine argument against allowing people to

Autonomous software is a lot more complex than the software the ECU uses (which is still complex), so there may be a genuine argument against allowing people to modify cars not designed for autonomous driving. It definitely raises a really serious liability question. Even with those systems working exactly as designed, there are some serious liability questions I don't think anyone has really answered yet.