Being considered a figment of somebody else's imagination is among the best defenses working to protect these creatures. Bigfoot is only considered real by a very small minority of folks who have made personal observations or had experiences that defy any other explanation.
It isn't very difficult to imagine how the general public will react to breaking information about the presence and proximity of Bigfoot creatures. Just consider what has happened during the past generation any time a rash of sightings or encounters makes news. Human nature is somewhat predictable; thus history tends to repeat itself.
For example, consider how the media and public responded to a series of incidents here in central Illinois. Over a period of a few months in 1972, a handful of credible eyewitness sightings of a single creature occuring here in the wooded ravines near my home in Tazewell County, Illinois (the creature was named CoHoMo by local reporters, short for Cole Hollow Monster) led to an organized sweep of Cole Hollow woods by dozens of armed citizens and law enforcement officers-- similar to what would be staged in the quest of a presumably dangerous fugitive. (For a summary of the 1972 reports, see http://www.geocities.com/bigfootman2320/cohomo.html).
Cole Hollow Woods occupies a series of steep ravines along Cole Creek with coal mine shafts (some once productive but now closed, some shut down before the laws were enacted requiring the entrances to be safely closed and others little more than exploratory holes) dug during the century preceding WWII. The effort was called off by the local sheriff's office when one of the participants was wounded by an accidental firearem discharge.
This was not some redneck "monster hunt" motivated by fear as described by some journalists, but rather it was a grassroots volunteer action by concerned neighbors trying to get to the bottom of whatever it was that was being sighted in these woods. Given what we now know about the elusive abilities of these creatures, I doubt whether any of the CoHoMo searchers in the summer of 1972 would have observed any evidence of the subject of their quest. But as a timely response to a local sighting report, it remains as one of the most ambitious Bigfoot search efforts when ranked by the number of participants (or "boots on the ground" in military terms).
When the Interstate 474 bypass was constructed in the late 1970s, Cole Hollow Woods became isolated from the network of wooded ridges along the east bluff of the Illinois River Valley. For the past decade or so, these woods have more or less become a playground for adults riding ATVs. These particular woods are no longer the same remote and inaccessible habitat area for woodland animals as they would have been back in 1972.
History will document the official re-discovery of Bigfoot as happening when somebody documents credible and verifiable evidence of the existence of these animals. The best evidence would of course be a body, but perhaps a high-quality video recording that shows one or more creatures in action doing something beyond the scope of human ability might be persuasive to many people.
When such a "discovery" takes place, we must anticipate the inevitable increase in fear of what is unknown among the general public, media, government agencies and leaders. Reporters will flock to outspoken Bigfoot investigators ranging from Eric B. to Tom B. and Matt M. for interviews and answers.
The survival of Bigfoot animals as a species will depend on how quickly fact can be sorted from fiction concerning these creatures.