I'm curious about this too. I don't use my Blackberry for tethering, but I have a Verizon wireless data card for my laptop. I was talking with a guy about the security of using the data card vs. an unsecured wireless network, and his comment was "CDMA has never been cracked". He didn't elaborate but I took that to mean using the data card is a lot more secure than an unsecured wireless connection. I would assume the same could be said for tethering with the Blackberry on Sprint since it's also CDMA. Not that I understand the technology... it's all Greek to me.