SCAM ALERT for La Paz, Bolivia

Recently I was walking down the street in Centro, La Paz, and ended up getting 'ripped off,' in an elaborate scam that fooled me -- I thought they were legitimate police, but turned out to be 'actors.' So, if a woman walks up to you and poses as a tourist looking for something, I suggest you turn around and walk away. I went along with it, even taking the woman's picture, the next thing I know descended upon by a man posing as police and asking for my passport.
I had made a small mistake, walking into a 'restricted area' (police tape), and thus I thought I was 'suspect.' These people very clever.
Additionally, I've had things stolen off my bicycle.
What's with Bolivians in La Paz, so much theft, begging. C'mon 'Evolution,' let's do something about this!
F.A. Hutchison, 'Hache' in Bolivia.