I think that any game with text or voice chat with strangers more or less automatically gets rated T or higher.

The DS has a built-in mic as well as a mic jack...so it wasn't really a surprise there. But yes...the Wii better get it soon...it's really necessary for setting up games.

@Non Sequor, that can't be true. Games that have online capabilities where you interact with other people don't change the rating, it simply says "Game Experience May Change During Online Play."

It seems like they could just use a Bluetooth USB dongle to extend the device limit. Each Bluetooth piconet can only have 1 master and 7 slaves, but a lot of piconets can operate in close proximity with only negligible interference (0.2% packet loss for two interfering piconets and 1.6% packet loss for 20 interfering piconets).

Every sub-T rated game with online play I can think of either has no communication between players or has heavy restrictions on communication (e.g. friend codes or restricting communication to canned phrases). While I can't find anything in the ESRB's guidelines expressly forbidding real online chat with strangers in an E or E10+ game, it seems like an implicit rule to me.

After all, I remember seeing local news channels doing stories about how pedophiles can talk to your children through Mario Kart DS and pictochat (I'm not making that up). If an E rated game with real online chat were released, it would attract tons of sensationalist news stories. I'm pretty sure the publishers are aware of this, and even if any publisher dared to include voice chat in an E rated game, the ESRB would likely use any trivial excuse to push the rating up to T.

Edit: Case in point: many fantasy MMOs seem to qualify for the E10+ rating (mild or fantasy violence and infrequent or mild blood) yet they're all rated T.

I guess so. I can't really remember any E rated games with voice chat...but then again Super Smash Bros is rated T. Mario Kart Wii will be rated E though, and I'm still hoping for chat there...I doubt Nintendo would want to rate Mario Kart T...

Yes...it would be a bit bulky possibly...but then 4 players could have 4 headsets...

 So long as they require you to use friend codes to chat with people they can get an E rating. After all, the friend code system was copied from Toontown, Disney's E-rated MMOG.