maps.google.com's crossdomain.xml file is as follows:
<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy
SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<site-control
permitted-cross-domain-policies="by-content-type" />
</cross-domain-policy>
Can you confirm that this effectively means "Access Denied" for Silverlight (and Flash), since there are no elements 'allow'ing any kind of access?