As a small counter to your post though, I've read some articles recently talking about the importance of general social networking and one on one mentoring in some professions with the point being made that if men in power in these professions adopt a stance of not being alone with women, this could impact women's ability to progress professionally compared to their male peers. I think it's important that if you adopt such a stance, and are in a position of power, that you find ways to mitigate the unintended effect it may have on women.
I actually have a male friend who was accused of harassment by a female subordinate that was later decided in his favor. Being gay, happily married, and from what I know of him a very good employee and boss, surely helped his case. After this incident he stopped all outside of work one on one meetings, but he did so with both men and women so no one is adversely impacted by his choice.