If Abraham Lincoln had heeded the warnings that his life may be in danger, the course of history may have been very different. In fact, if you look back through history, you'll find that there are almost always warnings history ignored, as well as times people who were right went disregarded. This unheeded advice from great minds could've changed the course of some of history's most horrific events.
Many of these people took stances that surprised their colleagues. Many were ignored because their predictions were assumed to be impossible. Lo and behold, however, all of them were vindicated later. But by the time everyone realized they were actually right, it was too late.
The take away? Just because an idea seems crazy, doesn't mean it's wrong.