A little something for a chuckle -- I've been testing Sprint's EVDO datacard setup this past week, and got a Kyrocera KR1 router for it (basically it's like a normal Linksys/D-Link except it uses the 3G EVDO pcmcia card for WWAN instead of a DSL/Cable line).
I set up a basic WEP wifi on the KR1 and it worked fine with the laptop, good speeds. I then turned on UMA and connected to the wifi (and opened the ports on the KR1), then made a call to a friend just to see what would happen.
It wasn't that great and dropped right away (and I couldn't get UMA back again for some reason) but it gave me a smile thinking of what the Sprint/T-Mobile/RIM network techs would think when they looked at their logfiles... heh.