This isn't a Band-aid, this is major funding for Mexico. It's the second largest cash cow. Vincente Fox no doubt will call this an economic attack on his country. This will force Mexicans to physically take the money back and when they try to cross the border with more than $25 G's it get confiscated. Use the money to pay for Border Guards.
Either that or it will force them to set up bank accounts at Bank of America for deposits, so people can withdraw the cash down in Mexico...
http://www.bankofamerica.com/newsroom/press/press.cfm?PressID=press.20030929.01.htm&LOBID=5