The world did not change when UFO's buzzed the White House and landed many times on government installations, and wreckage was found several times in the past. Reportedly alien bodies were recovered more than once and several million people have witnessed UFO's all over the world.
There is a fear that admitting that there are E.T's would destroy religions world wide, but all it would do is to serve as proof that our creator made many others besides us all over the Universe. It would show many who do not believe that there is proof that aliens exist and even with all the first hand evidence, there would most likely be some kind of cover up. Some people would never admit that there are other worldly beings despite of all of the evidence. I believe that E.T.'s would have tried to make formal contact long ago if they wanted to do so. They are probably afraid that we would harm them, or that it would be harmful to our society if they openly intervened. The subtle approach is one that they have been doing for eons. Crop circles, occasional visible demonstrations, and visitations, where the involved parties were well rendered unconscious, as they were approached, is the usual method of operation, according to several first hand testimonies. Furthermore, with the multitude of probable visitors from multiple star systems, it would be unlikely that we could safely say just who we were talking to and what motive they may have in coming here. I do believe that there are very good visitors, akin to angelic beings that oversee our society and, perhaps, manipulate things when they seem to get out of control and are hazardous to our future well being. All we can do at this point, is to guess about such matters and philosophize. We certainly will never know it all, despite all of our attempts to do so. The unknown and the search for truth has prompted human kind to search not only the mind, but try to gain insight into why things exist as they seem. As Columbus searched the seas for India many centuries before, we most likely will continue in our own personal quests in our thirst for adventure and the excitement of it all.