I ended up returning the Sprint Tab.
Although it worked great over WiFi, I did not want the dark cloud firmware and OS updates incompatibility hanging over my head.
Many people on the XDA Forums had the same questions and concerns. Nobody believed that firmware updates were possible without activation and 2-year contracted service. I am not very experienced with rooting/ROMs so I decided it was best to return during my 14 day window.
Since Sprint would not activate me with a pre-paid month to month contract, I had to exercise my right as a consumer to vote with my wallet and say no.
I believe that the firmware update may be a Sprint-only issue. I looked at a T-Mobile Tab and there is only System update possible (not four on the Sprint, only one of which (Android OS) can connect to a server through wifi; the other three, including firmware, attempt to connect via 3G). Likewise on my VZW Droid, there is only one System update icon in the Settings.
It's unfortunate because I really liked the Tab, but it was not 100% right for me. Browsing the web over wifi using Dolphin HD was a great experience, and much better than my wife's iPad, which tends to checkerboard a lot when scrolling.