In CANADA, the parent or legal guardian CANNOT be held responsible for the debts of a minor child, UNLESS it involves NECESSITIES of life, e.g. basic food, clothing, etc.. Even though minor children may think otherwise, NO software readily available to minors could be deemed a necessity of life.
Further to your comment, just because a person is forced to click on an EULA, does NOT automatically mean that the CONTENTS of the EULA are valid. Writers of EULAs do NOT have carte blanche to put ANYTHING they want into an EULA. It has to be LEGAL and REASONABLE.