From Blackberry's website
About Emergency Callback Mode
If your BlackBerry® device is connected to a CDMA network, when you end an emergency call, your device enters Emergency Callback Mode. This mode enables the operator to call you back or determine your approximate location. Depending on your service provider, Emergency Callback Mode is active for five minutes or is canceled when you make a non-emergency call.
In Emergency Callback Mode, you cannot send and receive messages or browse web pages.
Your device exits Emergency Callback Mode at any time if you make a non-emergency call.
This also applies to the Curve 8330 and is mentioned in both user guides.
ETA: Actually, I guess I'm one of the few. I do have the non-emergency phone numbers for my city/county police and state highway patrol, local hospital numbers, too. It's my SOP, but that's just me.