Why the re-post?
http://www.blackberryforums.com/gene...ap-8310-a.html
They may use the same data system i.e. 3G, but to use the native push email from RIM a Blackberry data plan is required.
This blackberry data plan allows for connection to RIM's servers, which is what the email push uses.
Without the blackberry data plan = no RIM server = no push email.