traveling with a large sum of money raises a huge red flag. They can seize it and you must prove it was legitimate. In the eyes of law enforcement those that travel with a ton of money are or have been up to something. There's numerous stories out there of (honest) people getting their money seized. Of course the biggest red flag is paying for your ticket in cash. There is no way I would take a sum of cash with me flying, the potential hassle factor is too great even if 99% pass through w/o incident. It's a money tree for the feds, and they don't need much "evidence" for seizures:
A) United States v $215,300 U.S. Currency (882 F. 2d 417 (1989) Ninth Circuit
In a civil forfeiture action, there was probable cause to believe $215,300 of an airline passenger was involved in narcotics trafficking, due to these indicators:
• carrying large sum of cash;
• canine alert for presence of narcotics on the currency;
• passenger’s attempts to avoid detection;
• passenger’s ticket was issued by travel agency known to have issued tickets for other travelers who had narcotics related currency;
• passenger’s nervousness;
• and passenger was bound for well-known center of illegal drug activity.
B) United States v $91,960 U.S. Currency (897 F. 2d 1457 (1990) Eighth Circuit
In a civil forfeiture action, there was probable cause to believe $91,960 of an airline passenger was involved in narcotics, based upon these factors:
• large amount of money in a briefcase, beneath torn phonebook pages;
• a notebook appearing to record drug transactions;
• the suspect provided inconsistent explanation as to presence of money, purchase of case, and his arrest record;
• dog sniff test indicated briefcase had been near narcotics;
• suspect was convicted of distribution of marijuana recently.
for more examples follow:
http://www.asctk9.org/id54.html