Might it be possible to avoid the abroad-unfriendly LAN site and book through an online ticket seller in Chile such as http://www.andinadelsud.com/ ? We might try doing some comparisons with folks inside and outside Chile, for some fixed date/time/origen/destination/airline set.
Even though falabella charges 2 lucas or so for buying tickets on their site, I believe they don't check for IP address origins and I believe you can access this site from outside Chile.... Auslanders please to check: http://www.viajesfalabella.cl/cs/
Sky Airlines doesn't seem to be messing with IP origin checking... I think
May be worth some experimenting.


