That sounds bad, but the truth is very different. I was at the meeting - NOT as a DOE contractor - and it wasn't an engine conference but the International Symposium on Combustion, a biennial international meeting that draws about 2000-3000 scientists from around the world to present their best science and to work together on technical and professional collaborations. Only about 40% of the papers are chosen for presentation and discussion. If you're doing combustion research on new engines, pollution prevention, coal use, laser diagnostics, forest fires, or a host of other topics, it is a must to participate. You simply cannot interact with that many of the world's combustion scientists by five-day videoconference. We can't really expect that the world's scientists always have to come to the US, either. The conference is held in the US every third time (every six years), next in San Francisco in 2014. The frivolous-sounding side events weren't paid for by DOE, either, and most of them weren’t set up for the scientists to attend, as they were in the meetings. The gala dinner was optional, and contractors were reimbursed only for the per diem allowance for a dinnertime meal (about $20). The Chopin concert and tours of Warsaw sights, the Polish royal castle and a day trip to the city of Krakow [after the meeting was over] were not reimbursable expenses but were optional expenses out of the attendees pockets, designed mostly for the "accompanying visitors," typically families, who naturally had to pay their own way if they came. If we want the US to retain its lead in science, US scientists have to be leaders. Paying for travel is pretty tightly restricted by universities and government labs, especially for foreign travel for the same reasons you have been concerned about.