Wow I suppose someone must be paying you to say this.Most wouldn't book the quarantine so there has to be a rule requiring proof.
Ok to your point, if someone doesnt book the hotel they can be fined at the airport and then escorted to the hotel. If I can prove my due deligence in trying to call the line with the best of my efforts, I will be awarded justice. If not I will pay the fine and pay for the hotel as well.
This is such a nightmare situation that keyboard warriors would never understand.