Probably. Best to use wifi to be safe rather than be sorry for the time being. Tonight, I just updated my BBM to include BBM channels, took a look around over wifi at home. I was wondering the same thing if I go some places and want to use BBM channels to simply browse using my data plan if free wifi is not offered at the public places. In the mean time, opt to use wifi at home and wherever you go for now. I will definitely check back here later on to see if any response comes your way from any experienced or heavy BBM channel user.
I've subscribed to 27 channels since beta version and all of it always give image updates. I spent max 40-50 MB a day including a heavy internet browsing, 1-2 hours reading news, IG, CB, twitter & BBM itself.
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