When I used to do security for concerts, we often had to do "full frisk" at the gate. Of course, even with full frisk there were parts of the body we just weren't allowed to pat down. At the end of the concert we would look at the floor and freak out at all the evidence of what got through. I'm not talking just small things like roaches and minibottles. There were fifth sized bottles, and more than just a few!
In training we were taught that special events work because very few of the people in the crowd are really out to cause problems, that is why there are usually only around 30 security people in a venue that holds thousands of people. The same is true with any security, flying is safe because only a few people who ever board jetliners mean to cause problems, for those who really want to cause problems though, all the searches, dogs and high tech equipment in the world won't stop them.