@starrynight - That's a good idea about getting your arrest record expunged. Not all arrests end in a guilty verdict, but some employers really do look negatively on having an arrest record of any kind.
I'm kind of fascinated by the idea of a citizens arrest. I feel like it's good that people can get sued if they do it wrong though. If there were no consequences to a wrongful citizens arrest, I think a lot of people would abuse it!