Carrier's liability is an old piece of legislation, dating to pre-9/11 times, and European and Asian airlines have routinely checked visas before people board, to keep out asylum seekers/refugees. Each non-visa-carrying passenger not given entry costs the airline something like $3000 the last time I checked. (They have to fly the dude back, too). The airline's assumption must be that Americans don't need a visa. Now Europe is much worse in giving visas. Americans are OK if you have a clean entry-exit record. I've had many foreigners assuming that they don't need an Indian visa. Those incredible India ads should say something like - come for excitement, come with a visa :-)
Salil Sent from my BlackBerry® wireless device
