While managing a hostel in South American I met people from all over the world with horror stories about security and customs while simply transiting through the US for a matter of hours.
Hundreds and hundreds of travelers told me they would happily spent $1k extra on flights next time simply to avoid the United States. They don't want to go there ever again.
The numbers don't reflect this though. Just looking at the first quarter of each year from 2006 to 2012 (inclusive), there have been more inbound arrivals in 2012 than there have in any previous years.
2012: 14,195,321 [1]
2011: 12,839,980 [2]
2010: 12,635,880 [3]
2009: 9,762,932 [4]
2008: 11,388,763 [5]
2007: 9,871,406 [6]
2006: 9,045,854 [7]
Quite simply, people aren't voting with their feet. In fact, any declines in people flying into the US seem to trend with the general economic climate.
The reason I picked the first quarter is because we already have the first quarter's data for 2012 and I couldn't be bothered to deal with the second quarter because this is only a quick glance at the data. :-)
I'm afraid I don't have time to. Perhaps this is an analysis you'd like to do though.
I will admit I haven't separated the entries by land/air/sea, as I didn't have that data readily available. The general trend still holds even excluding Canadians and Mexicans who may be more disposed to cross a land border. On the surface it just doesn't appear as though people are so turned off by the TSA that they're refusing to fly to the US.
It's quite amazing what people will tolerate in order to travel to and from the US. America's borders are sadly the most unfriendly I've encountered to date.
There are two regularly scheduled flights between Latin America and Asia. Yes, only two, unless you count a connection between Sao Paulo and Qatar.
They run between Mexico City and Toyko and between Mexico city and Shanghai, with a fueling stop one way in Tijuana. The flights are operated by Aeromexico.
There are many, many airlines that want to sell you a connecting flight between Asia and Latin America through LAX or SFO. The two flights that don't pass through the USA charge a $5-600 average premium over the flights that connect in the USA for the cheapest tickets.
So that's what avoiding the USA customs and TSA procedures is worth in the market: $5-600, round trip.
Hundreds and hundreds of travelers told me they would happily spent $1k extra on flights next time simply to avoid the United States. They don't want to go there ever again.