All entrants must presentation a certificate of inspection within 72 hours before leaving the country. If you are unable to presentation a valid certificate of inspection, you will not be allowed to enter in Japan based on the Quarantine Law.
・In the country of departure, if you do not have a inspection certificate before boarding, you will be denied boarding the aircraft.
・In cases where it is difficult or truly unavoidable to obtain an inspection certificate, please consult with the diplomatic mission abroad.
結局は親が決める事だから、受けないでもし問題が起きてもそれは自己責任なだけ。多くの人が無事入国できてるのは現実的にあるみたいなので大丈夫なんでしょう。ただ引っ掛かるのは厚生労働省のサイトに新着情報で重要情報としてアップされた件。はっきり書かれてますよね…All entrants must presentation a certificate of inspection within 72 hours before leaving the country.