I've read of cases in the US, where kids were buying cars and other expensive goods using their parent's eBay account
A minor cannot enter into a legally binding contract without parental consent. That includes online purchases. So the parent can rescind the purchase.
So if my kid purchases a $800 item online, I can contact both eBay and the seller and they have no choice but to cancel the purchase. Some online sellers have tried, but failed to complete online purchases made by minors that were without parental consent.
Good grief man... can you just imagine if an $80,000 Mercedes was delivered to you by someone who is not Santa Claus because of something an 11 year old did online ?
as adults (who are not
knowledgeable on internet/computer security) do the clicking on the "Next" button very often and ignore the warning pop ups too!... or not? Maybe they should be locked out of the system too... or they would be safer using Linux or a Mac?
Adults in some respects take much greater risks.
Unknowledgeable users of any age benefit greatly from strict default-deny.
The kids can figure out Linux way before most adults. Linux makes most adults have meltdowns.