We have seen what this creature is capable of and respect is the best defense. Something as little as making direct prolonged eye contact can bring on aggressive behavior. These creatures are much like humans in the way they "take things" in general. Some will quickly leave and some will not. Some might take offence at your simply being there and some might not.
We think the best thing to do if you run into a Bigfoot closeup is to back up slowly and don't make any quick moves to alarm it.