The fog is getting thicker, and leon is getting larger

More bad news on the Windows Meta File front.
According to the latest SANS ISC Diary, McAfee announced on the radio yesterday they saw 6% of their customer having been infected with the previous generation of the WMF exploits. 6% of their customer base is a huge number.
How does McAfee know how many infections occured? With Symantec my clients aren’t reporting anything to them. Does McAfee have all client infections reported to them (both consumer and corporate)?