I had to buy a return ticket for the 1st time flying Delta from JFK in Jan 07. THis is after years of traveling at least 2ce a year from and to SDQ w/o return tix. The Delta ticket person said her computer wouldn't let me check in for my return flight (I was on the last leg of a round trip from SDQ, where I live) until I bought a return ticket within the legal window, which is 30 days, down from 3 months a while ago. I just bought a full fare tic and got it refunded here at Delta. Annoying, but it turned out to me a minor issue. AA threatened the same thing once, but I had a letter from my job and they didn't hassle me. I think the airline enforcement of this rule is a bit arbitrary, and it's true, Dominican migraci?n couldn't care less (although it's their law).