Any comments on blocking SiteAdvisor spider
 

The purpose is to avoid the red rating. No rating is better than being blocked by their tool bar and suffering the red x on the SEs they support.

Options in blocking could be robots.txt or htaccess or block the IP(s) on the server.

Don't how effective a block could be or how they would react.

Looking for comment.

That would be wether you deserve the red-x or not. I was thinking more along the lines of a false positive or they scan on a day you suffer some hack which you quickly fix as soon as you can...