What a sad social commentary. In my career I've often had female bosses and the thought of not meeting with them one-on-one on a regular basis is ridiculous - there is no way we could have had an effective working relationship or organization otherwise. 

I also think the idea of not having a dinner or drink with a boss or co-worker of the opposite sex requires context - I've often had lunch or dinner (with a drink) with a superior or subordinate of the opposite sex to discuss work, which is entirely fine to me and very different from doing the same just for social reasons, which would not be entirely appropriate.

I think avoiding such situations to "avoid temptation" is a reflection of the moral character of the individual if they think they're unable to "resist temptation".