Probably the cost. There is a single Sunday 11AM flight to Serbia, so I pleaded for Monday if possible at all (my exact words). They still rather chose to fly me out of Hungary (that's a whole different country there, requiring a fun combination of car, long distance bus and a 4 hour train ride ). It IS cheaper to fly out of Budapest though (plus the room cost for the night) - they never explicitly said money was the issue - just picked that option... But hey, travel is adventure, and if that extra money can be used to secure direct flights for you long range folks or help the budget of the Summit in other ways, I'll gladly spend those extra few hours coding/surfing/prepping images for flickr/blogging about Summit impressions on the train