Originally Posted by JDiver

Every nation has different entry / departure requirements, and every pair of countries has their requirement for travel between them. It is up to the airlnie to enforce them, and up to us to make sure we meet all the criteria required to permit us to travel, even if they appear somewhat bogus or picayunish...

It seems every year I run into folks who persists in ignoring these, and penalize themselves - the young couple I saw turned back at the border with Tanzania in Namanga, the several I saw turned back at the border at Iguazú, those not permitted to stay at destinations requiring visas or ongoing tickets... the woman who persisted in arriving at Lilongwe in trousers some years ago (she knew the "the Ngwazi, Doctor Hastings Kamuzu Banda, President for Life" required dresses of women, and short hair for me, but decided to fight it... ) And I've never seen any one of them get satisfaction.

Someone visiting, even with a yacht in, Costa Rica, without citizenship or a permanent (inmigrado, residente, pensionado or inversionista) status, require "Tickets and Documents for return or onward travel" and the airline must enforce this requirement without official documentation from the Costa Rican government waiving that requirement. In fact, depending on how the OP departed CR, he could have some legal issues on his return.

Yes, the easiest would have been to buy a full price, fully refundable ticket and cash it in later, rather than a cheaper, non-refundable ticket (which the OP could possibly still something out of it by making a change - including transferring the name, maybe - paying the change fee and using it.

(Hint: An MCO is often acceptable to immigration authorities.)