I have to say "I don't know."
Honestly, I think the odds are against it, BUT there are still HUGE tracts of uninhabited land in North America, and Asia where a Sasquatch or Yeti (bipedal primate) type creature could go undiscovered for many years. However unlikely it is that such a large mammal could stay hidden so well, I cannot say that it is 100% impossible. The Mountain Gorilla in Africa stayed a ghost till 1902.
I do believe most sightings are either a hoax, or mistaken identity, and sadly most documentaries and TV programs on the subject are a total joke. The most credible researcher I've heard on the subject is Dr. Jeffrey Meldrum, a proffesor of Anatomy and Anthropology at Idaho St. Like me he's smart enough to say "I don't know" when it comes to existence of such a creature. But his research has claimed to have turned up some evidence in footprint casts that is not easily dismissed.
So I say, odds are against it, but I won't rule out the possibility entirely.
EDIT: Watched the ABC video, on that Animal Planet show... I watched it once because they where in my neck of the woods... and.... that show is an absolute joke. To call those guys "researchers" or "scientists" is an insult to serious researchers in the field.