Apr 11, 2015
Summit Stock 2015
“On Wednesday, August 13 (two days before the Festival was to begin), there were already approximately 50,000 people camping near the stage. These early arrivals had walked right through the huge gaps in the fence where the gates had not yet been placed. Since there was no way to get the 50,000 people to leave the area in order to pay for tickets and there was no time to erect the numerous gates to prevent even more people from just walking in, the organizers were forced to make the event a free concert.”
http://history1900s.about.com/od/1960s/p/woodstock.htm