Bail & Bounty-Hunters - for real?

In addition to my SDMB addiction (see http://www.straightdope.com/ubb/Forum4/HTML/000573.html , I am also a non-recovering L&O addict on A&E (although what will happen in the fall with the time change moving it late in the night I shudder to think).

Watching it, I've got a few questions about U.S. criminal procedure.

A. Bail - the only thing they seem to discuss on bail is money, and great gobs of it. Under U.S. law, can't the court consider things like flight risk or risk to the community directly, or is the money always a surrogate for these types of concerns?

B. Bail seems to be posted by bond companies, who have no personal involvement in the case. How does this work? How do they make money off it? Does the accused pay a premium to the company, like regular insurance, which the accused never gets back?

C. Bounty-Hunters - is this for real?!? Both L&O and Homicide have had cases about bounty-hunters. Didn't that go out with the closing of the frontier? If they do exist, and are exercising authority granted under state laws, how come they don't have to comply with constitutional protections, like search and seizure law? If their authority comes from the state, don't they become state agents?

So, what's the Dope, you SDMB lawyers? Is L&O just stretching the law for "dramatic effect," or is it relatively accurate? and if the latter, how does it all work?

Any comments would be appreciated.