On an idle Saturday, I happened to be scanning twitter, and I saw this from @AirlineReporter:
From the Idaho Statesman – and believe me, the title of their article is poorly done, but here it is –
Passengers evacuate plane at Boise Airport after fuel leak sparks fire fear
It appears that the reason they decided to have a party on the wing, was due to a fuel leak that looked like it might be vaporous (this the “spark” comment in the title). Apparently many felt it was better to be out, standing on the wing, in the event the fuel spill turned into something, rather than in the aircraft. I don’t see the fuel spill, bu the fact that the fuel truck is in the background doesn’t make me feel like that was good idea.
Oh, and check out how many bags are on that wing… looks like there is in fact room for a rollerboard on the wing, because, why not?