Call me a cynic, but I tend to lump all the Sasquatch sightings and U.F.O. / Area 51 hobbyists, in with the Loch Ness Monster and guys who wear tin-foil on their head to stop the government from controlling their thoughts.
I suspect that in the vast majority of cases, such sightings are simply the result of over-active / over-tired imaginations, mental delusions, or have been induced by alcohol or drugs.
Yes, I recognize that there is a spiritual realm and that demons do exist, but I also believe that Satan is now chained and that demons are not as powerful or common place (in so far as they are made visible to us) as many would have us believe.