I've heard of it, and our western MA S&R folks allegedly had some "expert" trackers as well. However, one boot print does look like the others...and, honestly, if you're lost on a trail, someone will find you eventually. ITs the more subtle tricks of off-trail tracking where skill comes in; a bent branch, kicked stones, etc. Usually (hopefully) with a partial track here & there. But, human trackers are, honeslty, the worst. USe a dog. Most S&R teams have air & scent dogs. They can track for days, and dont require visual confirmation. A human tracker would be an absolute last resort. At least, thats been my experience.