Do cruise companies 'cover-up' these crimes because they're bad for business? I'm sure they do. Are they right in doing so? No they're not.
In the end, the best person to entrust your own safety to is yourself. do not mingle with strangers. Do not get yourself so tanked up you don't notice someone tampering with your drink. Do not go to the bars and clubs by yourself.
With all the traveling I havedone, I've never come close to being a crime victim. It's not really that hard, but you do have to consider it your responsibility.