I had a polycro groundcolth from gossamer gear a while back. It was super fragile stuff. I looked at the GOLD website but could not find if their tarps were made from a thicker plastic than what I used for a groundcolth....
I would be real concerned using this stuff as a pack cover or a poncho. I can see using it as a tarp in calmer weather, but I can't see the polycro lasting all that long in an abrasion prone situation....