Earlier quoted context omitted.
There is nothing 'arbitrary' about this. He committed financial fraud and got caught out when sending in documents.
He did not commit financial fraud. He might have broken a TOS, but bringing up financial fraud is just silly. Honestly, in many jurisdictions (except for the punishment happy ones) being under certain age, ie. 18 or 17 automatically makes you non-persecutable for a lot of the "soft" offenses. So even if you tried to claim opening a PayPal account is a financial fraud, it would likely never stand up in court.
If the TOS includes the terms (1) you certify that all information provided to us is accurate (2) if you breach the TOS you must stop using the product and (3) you certify that you are over 18.
Then your continued use after age 18 may in fact signify entering a contract, even though you were under 18 when you signed. It also may not. Capacity/consideration/intent to be bound are really tricky in this case.