My only suggestion besides all that you can do there is just to watch for your stuff, your wallet and cameras. try not to look too turistic. There are many pocket pickers there…..I saw one time in the subway at rush hour how a guy open a turist’s bag in front of him, smiling at him and taking the money and a camera. The subway was full and each person was againt to each other. That’s why they were face to face….smiling….and getting robbed. I couldn’t say anything because behind the turist there was another guy watching for the first one steeling.
I dont mean to scare you, Santiago is a safe place, but it’s just like any other big city.
Enjoy your trip, it is a beautiful country, specially the south.