they DID it:

"Starting this week, all U.S., Australian or Canadian citizens arriving in Buenos Aires, Argentina, must pay a fee of up to $131 before entering the country.

The entry fee, which applies to revenue and nonrevenue passengers and all other pass riders as well, will be collected at the immigration desk upon arrival at Ezeiza International Airport in Buenos Aires. American citizens may pay in U.S. dollars, by credit card, or with travelers checks. The $131 amount is equivalent to the charge that Argentine citizens pay for a visa to enter the U.S.

Once paid, the fee permits multiple entries into Argentina for 10 years in accordance with U.S. visa reciprocity. The Argentine government previously has said it would drop the entry fee if the U.S. and other countries cancel their visa requirement for Argentine citizens."

woe is me--that steak just got REALLY expensive