Maybe this thread explains why some organics are being blocked
http://answers.microsoft.com/en-us/w...1-4371c27ca816
EDIT: i just googled Mozilla/4.0 (compatible; MSIE 999.1; Unknown)
Test driving the useragent at
http://www.botsvsbrowsers.com/Simula...%3B+Unknown%29 shows:
Method: GET
Request Status: 200 : OK
Content-Length: bytes (~k)
Content-Type: text/html; charset=ISO-8859-1
Server: WebServerX