a4 - I was aware of his blog entry (and actually linked it in a previous thread here). However, this has been the only time I've ever heard of anyone being allowed to do this.

What's different is that Seth was entering/leaving EZE at a time when if he was refused free entry he could have remained airside, or could have paid the reciprocity fee at one of the airport booths. Neither of these possibilities is available to you (there are no payment booths at airports anymore - you must pay via the internet beforehand).

Also, there is no paper form anymore that could be stamped - it's all done electronically including a thumb print and head shot. Seth mentioned that he had done everything in English, but in my extensive experience, the immigration officials on the whole speak very little English.

Paper documents showing onward travel are obviously easy to fake, and immigration has no way to easily verify whether they are valid. AR might actually refuse to board you in GRU until you have proof of payment of the fee. To leave Argentina you also need to have a stamp in your passport showing when you entered the country - if you have overstayed your visa, the airline will not check you in until you have paid the overstay fine at the airport bank and can show them the paperwork.

I don't know what the Argentine law actually is (and I doubt whether you'll be able to easily determine this), so it might depend on what immigration at AEP does ...

If you possibly can, change your flights to a direct GRU-LIM, or via a connection where you can stay airside. The best flight to take would probably be on LAN. Are you staying in Peru or do you have to catch another flight after you land?

John