A weird thing related to Android 2.2 call receiving functionality.

I have now about five 5 days since I upgraded my Nexus One to Android 2.2, and the phone still doesn't stop...impressing me. I've observed that if I receive a call from somebody and I am near the phone, I can hear the voice of the person who's calling me. For example...if a friend is calling me and near him is a person to which he says something while he calls me (my phone is ringing), I can hear what he says.

I don't know if this is a bug in the Android, a malfunction of the device, or this is something normal, because I wasn't able to find anywhere else something related to this thing. I am really...curious if this happens to anybody else, and if it does, this means that it is possible for those ones with Nexus One devices and Android 2.2 to speak for free, but for a limited time, because the call stops after 10-20 seconds (depending the carrier).

So, does this thing happen to you too?

p.s.: If you need to update to Android 2.2, here's how to do it.