This is pretty simple.  Siberian Huskies have been bred for generations to outperform other dogs when it comes to endurance and stamina.  No matter how much training and how trustworthy you feel your husky is, if he is let loose he will run.  Farther and farther away from you.

Just like the husky has a prey drive they also have a "run drive".  Their eyes kinda get a glazed over look to them and they're off.  It is absolutely no fun to chase after and try to find one of these dogs once they get loose.  I have years of experience with it, I'm not kidding.

Sky and Star got loose about a year ago.  I searched for hours.  I got a phone call from a gentleman 4 miles away saying he had caught Star and had seen Sky but couldn't catch her.  He lived a mile away from the interstate.  Sky finally came home of her own free will 2 hours later.

Now let's analyze this situation.  What if I lived in a suburban neihborhood instead of out in the sticks?  Well that 4 mile jaunt could have resulted in:  a.) dog is never found  b.) dog gets hit by a car  c.) dog get's picked up and stolen never to be seen again.  There are many variations that could be explored but that should give you an idea of the most common.

So please, never let your husky loose in an uncontained area.  No matter what.