Please review our document regarding customer-specific spam submissions:
http://www.symantec.com/business/support/index?page=content&id=HOWTO77718
Here are the revelant parts for your query:
When you configure this feature, administrators and end users can submit email messages to Symantec as missed spam or false positives. Within minutes, Symantec creates a custom ruleset. The conduit obtains the ruleset, which is then applied to each configured Scanner.
Symantec considers all messages that are submitted as Spam or NOT Spam for global rules regardless of whether the customer-specific spam submission feature is enabled.