[Update: The Register's John Leyden has also commented on the issue at http://www.theregister.co.uk/2010/02/16/apple_bans_iphone_hackers/]
There's been a burst of interest in the last day or so in the blocking of certain Apple IDs from the iTunes App Store. Some bloggers have suggested that this might be a precursor to a massive blocking of jailbroken phones from accessing the App Store.
However, the reports I've seen all mention only two specific IDs, both of associated with individuals who are well known as having publicised vulnerabilities, so it sounds to me as if this measure is specific to individuals perceived as posing a security threat, not as a means of punishing jailbreakers by denying them the opportunity to pay for legitimate, approved apps supplied by software houses with whom Apple has a commercial relationship.
More comment on this at Mac Virus here and here. Also, thoughts on the Wholesale Applications Community which brings together three of Apple's major competitors in the mobile phone industry and a large group of major telecoms providers.
David Harley CISSP FBCS CITP
Director of Malware Intelligence
Securing Our eCity community initiative: http://www.securingourecity.org/
Author David Harley, We Live Security