interesting point i think to clearify these discussions wouldnt it be better to discuss what codecs are used, supported, amd i know 4G has encryption and 3G does not, who owns the keys etc, if voice and data can use the same basic internet protocols or ride on them then the network provider wouldnt be all that much wiser what you are using the phone for (assuming it is encrypted and you have the keys).
A way to circumvent the whole blocking you can just tell the provider its a hotspot device that typically has worked for me in the past (also means no voice using tradition service though).