Question about Newly Registered Websites and best practices

Hi,

I was doing some checking on activity in the Extended Protection: Newly Registered Websites.

I want to block this category by default because I can see how a number of sites might be exposing our environment to undue risk.

Question: How long does a newly registered website remain in this category?  (day, week, month?)

In the last week users hit over 100 unique sites in this category and few of these sites seem legitimate. I do expect some resistance and think having an answer to how long the sites remain in this category would help ease their concerns. I am guessing that if a user complains we can follow the normal process of recommending an alternative category to Websense as well.

Question 2: Is it a best practice to block un-categorized sites?  I am hesitant to suggest this because I see that in the last week users have hit over 5,000 sites in this category, and I know a large number are legitimate.

Thanks for any responses.