Alert citizens (aka HUMINT) play a much larger role in stopping terrorism than you would think.
Much like CCW can stop spree killers, anonymity software allows citizens to safely submit tips without the fear of retaliation.
Who knows what could have happened because the witness in the link above feared retaliation for being wrong about what he overheard.
- Anonymity (safecomms.wordpress.com)
- Free Anonymous Proxy Servers: A Complete List (networking.answers.com)