Yep, programmers will screw this up, and that's where good docs and good easy to use implementations come in.

I also believe there's a market for auditing people's use of services like this. At the point where programmers can screw it up you just can't invent better tech to make them less stupid, so a better approach is to have social elements. Badges saying they're audited, documentation, good examples doing it right, well done APIs, etc.