Jailbreaking isn't like opening the hood, it's effectively messing with the system and setup (just like the ECU example). It might not cause any problems, but it also might.
I have no problem with that by the way, but you are on your own lookout and should accept it as part of the deal. Similarly if I damage engine performance due to bad tuning it's my problem, not theirs.
I do think it's too broad of manufacturers (whether car or phone) to apply a blanket warranty denial in such cases. But in the phone case, no reason apple should accept bug reports on a jailbroken system if it can't be reproduced on a "stock" one.
I have no problem with that by the way, but you are on your own lookout and should accept it as part of the deal. Similarly if I damage engine performance due to bad tuning it's my problem, not theirs.
I do think it's too broad of manufacturers (whether car or phone) to apply a blanket warranty denial in such cases. But in the phone case, no reason apple should accept bug reports on a jailbroken system if it can't be reproduced on a "stock" one.