WHERE VACATIONS START!
It is now "required" but not always enforced, that you should have a ticket showing you are leaving Panama upon arrival at Panamanian Immigration (at the various Costa Rica border. So, how safe would it be to simply book a reservation on Copa (held for up to three days without paying) and take that reservation with you to show in case you are asked?
I have in the past used a paid for ticket on United, that you CAN get refunded but only when cancelled within 24 hours.
Copa won't refund a ticket without penalty as is shown here
and be aware I am in process of getting a Pensionado to avoid this problem on-going, but i need to do a couple more crossings beforehand.