Ah, VFR. Now this question makes more sense. The relevant regulation is 135.213
"(a) Whenever a person operating an aircraft under this part is required to use a weather report or forecast, that person shall use that of the U.S. National Weather Service, a source approved by the U.S. National Weather Service, or a source approved by the Administrator. However, for operations under VFR, the pilot in command may, if such a report is not available, use weather information based on that pilot's own observations or on those of other persons competent to supply appropriate observations."
I would interpret this to mean that if the weather report is available you must use it. Perhaps you can make a legitimate argument that the AWOS is defective or broken. I have seen this in reality (AWOS reporting 1/8 mile visibility and the weather is severe clear) and in that situation I believe you would be justified to ignore it ( and perhaps make a report to the effect that the AWOS is not working). If the situation is more borderline I think you could be digging yourself into some legal trouble.