When RIM introduced the PlayBook, it did so without an email client, but not to worry you can download BlackBerry Bridge and tether the PlayBook to your BlackBerry. Or maybe not.

[ad#Google Adsense 300×250 in story]It seems that AT&T may be blocking the BlackBerry Bridge due to tethering restrictions, according to CrackBerry.com. Even a note on BlackBerry’s App World says the BlackBerry Bridge software is supported by all carriers, except AT&T.

What does this mean? Well, the PlayBook users on AT&T can’t check email at all.

Perhaps RIM didn’t do its homework on which carriers would allow PlayBook to BlackBerry tethering. But that doesn’t make much sense, does it?

BlackBerry App World has a note on launch day that the software isn’t supported on AT&T, so did RIM know and just not tell its customers?