Pax would be told maybe 24 hours before departure if it converted to a real seat or a refund/credit voucher
How would this be diferent to walking up a nd buying a ticket on the day? You've still been given a specific date/time. They would have a reservation -
"reservation" means the fact that the passenger has a ticket, or other proof, which indicates that the reservation has been accepted and registered by the air carrier or tour operator;
I realise such a solution might require a lot of legal creativity... so maybe the "tickets" might be sold by a company in an offshore jurisdiction which is not formally owned by the AOC licenced airline but which "advertises" on the airline website and pays "consultancy fees" to the airline
Would still be the operator who is responsible -
"operating air carrier" means an air carrier that performs or intends to perform a flight under a contract with a passenger or on behalf of another person, legal or natural, having a contract with that passenger;