One time I landed in SDQ and I was hassled a bit. But not forced to buy a new ticket, they just reiterated that I can't stay for more than 30 days on a tourist visa. Other times I land in PUJ, and well...let's say that airport has the easiest immigration in the world. ie. 'welcome gringos, spend your money, stamp stamp stamp'. If al queda wanted to enter dr, that would be the airport to land into.