"Free" stuff always gets mobbed. Like when I was in 7th grade The Cranberries ("In your heeeeeeaaaaaaad! What's in your heeeeeeeeaaaaaaad?" Remember them?) put on a free concert in downtown DC. Me and some friends skipped out of class and took the subway downtown. The concert only lasted like three songs because the crowd got out of control and too big, so the band dipped.

Free stuff, always gets mobbed.