Instantly identifying a sexual predator

I petition that all child sexual predators be marked or tattooed visibly with some marking for the safety of our children. Rehabilitation is practically obsolete in the particular offense. They are getting out of jail and reoffending repeatedly. Our children's innocence is being stolen. There has to be a way to clearly identify who they are so proper procedures can be taken. The number of repeat offenders is quite frankly overwhelming. How can we keep our children safe when offenders are at our parks, skating rinks, and bowling alleys? Just waiting for an opportunity to harm our children. Something has to be done before more children are harmed. The safety of our children needs to be our top priority. Unfortunately, our children are being raped and killed while this pattern continues.