Originally Posted by Helmet Head
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But my point is that given that you are operating defensively, the bad drivers are no longer a serious threat.
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Okay, that's fine. However, operating defensively means being in an active state of "worry" or "concern" about whatever traffic situation you are in. Its not like a binary decision to "not drink from toilet bowls".
For the case of the cyclist, I would go even further and say that
the cyclist must be more alert to traffic and potential problems simply because the penalty for failure is so much higher than for a car.