To All, I just (february 2016) returned from a trip to Nicaragua with my Phantom 3P. Drones are still NOT allowed in Nicaragua! By no means. Even though nothing is posted anywhere on-line (besides this one thread) about drone rules or regulations in Nicaragua, there is no sense in bringing your Phantom and trying to get it cleared at customs... All your luggage (hold and carry-on) is X-ray scanned BEFORE leaving the airport in Managua, and of course the shape of the Phantom stands out clearly, after which confiscation is inevitable.
Yes you can get it back upon leaving the country, after having handed in your receipt of confiscation, a copy of your passport and of your tourist visum (don't forget!) and of course the storage fee of 3 US$ per day in storage (cash, in Nicaragua Cordoba's). You can get it back when you return to the airport to leave the country again, after having checked in, by going to the customs office (an unmarked white door in-between two rental car desks), with the required paper work, going through the passes and paying the fees. An armed guard will take you and your phantom straight to security to go to your gate, so you cannot 'sneak' out the airport with your Phantom. So don't even try. And stay polite and respectful to all customs officers. That helps.
NOTE: CUSTOMS OFFICE HOURS ARE MO-FRI 0800-1600!!!! if your flight leaves Saturday or Sunday, make sure you pay your storage fees during the MO-FRI office hours!!!! and hope that a customs officer will go get your phantom from storage for you upon showing your boarding card and payment slip on your (SA-SU) day of departure.
Maybe having your Phantom confiscated and stored at the airport at customs is a good thing. I would not want to find out the consequences of being arrested while flying one in Nicaragua. Really - not. Officials hate/despise drones because they wreak of espionage, apparently. And I was there to get aerial shots of a new neighborhood for the poor build with international aid money, to record the huge positive succes which was attained with this cooperative project.