1. In my opinion there should be a zero tolerance policy for sexual harassment. If you are found guilty of it I think you should be fired right there on the spot. I don't care if the person being "harassed" is at the same level as the harassor or if they are a superior and a subordinate. No one should have to deal with that in a work place. Now the issue would be was it without a doubt sexual harassment or does it fall into the gray area.
2. If a sexual harassment claim has been made the human resource department should investigate the claim thoroughly to make sure the claim is valid. If the claim is found to be invalid the accuser should be either terminated.
3. I know there are some cases that would fall into the gray area. Not every case is as clear cut and isolated to one event. Sometimes there are cases when a female coworker could be wearing a outfit that is not 100% appropriate for work, as an example. A male colleague could say something to her about her outfit that was not meant to be sexual but that's the way the female coworker took it and reported him to HR. In this case what the male colleague said could be taken out of context and in an absolute zero tolerance policy he could be fired on the spot. There does need to some room for these types of situations and others like it. An investigation needs to be had by a non biased person, the work record of the people who are involved should be taken into consideration and a counseling session with the outcome of the decision. Perhaps if the male colleague, in the presence of a neutral third party, explain what he meant by the comment about her outfit the female coworker would understand better.