I had my laptop stolen at the Startup Chile office and the Startup Chile team helped me get it back because of surveillance cameras. I am the only person this has happened to (at least from what I know). I think you can get things stolen in any co-work environment and there is no way Startup Chile can control this (other than doing what they already do).
If you are uncomfortable with the security aspect you can get an office for around $600/month (I am currently sharing an office with an Argentinean company and we split things $300/month). Our office is rather large (it's 3 offices, one bathroom and one kitchen).