Honestly, whether or not I think this is cruel and unusual depends upon what the person did. A penis isn't necessary to hurt children. If someone actually has sexually assaulted kids, then they should not be allowed to live near a day care centre, period--I don't care if it's been 75 years. (That said, they should get help with the moving expenses and arranging the move and all that what not from their parole officer or supervising agency.) There are some sex crimes that I don't think you should be left unsupervised after even if you have proven you should be let out of prison/jail.

However, there are an awful lot of sex offences on the books that shouldn't rate this level of scrutiny; I've heard of people who have had to register as sex offenders simply because they got caught fucking out of doors, or because they had consensual sex with a 14 year old who looked and acted 19 and lied her arse off--and I can't imagine you being friends with someone who actually raped a prepubescent child.