There's no reason why anybody should fear calling in fatigued, provided that they don't take "advantage" of it. During my roughly 5 years flying the line for a 121 carrier, I called in fatigued 3 times. Each time was a situation where the schedule had been manipulated due to weather/delays/mx, and had resulted in odd circadian patterns and excessive duty time.

Each time I explained why I felt I was unsafe to the CP, and each time I headed to the hotel. Did the company want and explaination? Sure. Did the CP ask me if I felt that I was truly unsafe? Sure. Was there any disciplinary action taken- not in your life.

I can almost guarantee that every pilot on this forum that works for a 121 carrier (and most 135 operations) have somewhere in their flight ops manual a chapter about company safety. In there is going to be a "safety letter/statement" from either the CEO, President, VP of Ops, or Director of Safety that essentially glosses over the "safe operation of all aircraft at all times" and how "employees observing unsafe operations will take steps to stop them immediately." (You know- the usual yada yada that every company speak, but might not necessarily follow).

That right there is your largest weapon. Call in fatigued and get disciplinary action? Call the media and call a lawyer. If you take good faith action to remove yourself when you feel unsafe and lose your job as a result of it, you can better believe that the company is going to be hard pressed to defend itself against public opinion and a jury/judge with such a statement as policy.

Remember- document, document and document. Then stand up collectively as a group and say, enough is enough. The more folks that file complaints with the Department of Labor, OSHA, Congressional Reps, the FAA, etc, the more likely the pressure to change will be.