I used to volunteeer at the conventions and was always appalled at the lengths that "security" went through to hide that fact that a known paedophile was right there int he midst of the audience.
Sometimes the abuser would comply and sit in an allocated place so "security" could keep an eye on them, but more often than not, they would give "security" the slip and disappear into the toilets etc.
A year never went by without some attempted abuser abduction on some child and yet it was NEVER reported.
It was sickenig.
I always used to let families know when there was a known abuser there. My conscience would not allow me to keep quiet and yet I was the one seen as a trouble maker!!!