I non-revved in there with my daughter in Feb '13 and we both had to pay the Chile fee as neither of us had been there before. There was a reasonably organized system, with a ticket window setup (sorta looks like any other int'l stations immigration queue) where I swiped my credit card, got our stamps and we were on our way. I know that doesn't help you much as a working crew, but we did end up going through customs/immigration right with the Delta crew that flew us in - we probably got off the plane 10 minutes before they did being in the first row of Economy comfort.

Bottom line, if your wife gets off the plane quickly and near the front of the line, she shouldn't be too delayed getting through the reciprocity tax line, and you could meet up with her prior to hitting immigrations/customs. Have fun SCL is a blast.

Edit: to follow-on, ~ 1/3 of our flight seemed to be Chileans who obviously don't have to pay the fee. Also, anyone that already has the stamp doesn't have to stop in the line. It is not a choke point when you pass the reciprocity line (meaning the Chileans/those with stamps just keep walking.) I think we were in/out of that line in 5 minutes. You could have her hustle off the plane and then just meet her just past the reciprocity tax line, where she will probably be finished and waiting for you.

Also, be aware that when non-revving out, they don't clear standbys until they are given a seat. So if you're working, you will already be on the airplane and won't really know if she's going to make it or not. We got to the airport 2-3 hours before departure, and ended up waiting around at the ticket counter for our names to be called - which was 20 minutes prior to push. We then ended up hauling ass through a very slow security/immigration (again for some reason?) line and ended up getting on board right at last call. That was definitely the most stressful part of the SCL airport experience. Arriving was a breeze, getting out not so much.