Ok ticketing experts out there, here's a tough one.

I have a hand-written paper RTW DONE4 ticket. I had 19 segments used up on it and 5 NA segments, so in order to try and maximize the mileage flown I stuck in a "duplicate" segment. What I mean is that I had the original itinerary set up like so:

JFK-SJU
SJU-JFK
SJU-JFK <-- my plan was to buy a one-way ticket to SJU and just make it a mileage run.

My paper ticket still has coupons for both SJU-JFK segments. When the electronic itineraries were "ticketed" though, they cancelled the second SJU-JFK segment for whatever reason. I decided that I didn't want to make a stink about it and just let it go.

So.... what happens if I show up at the airport in SJU with a paper coupon for this flight (has an actual date and flight number written on the ticket) but there's no record of my reservation in the computer?