It just means AT&T has a oversubscribed network. When a telco runs a network, they run on contention ratios, 1 tower for X subscribers, when that tower hits it's limit, often more network infrastructure is built to cater for demand.
Now the marketing dept has the job of selling the network, they offer so many gigs per month per plan with the belief most people will only use a fraction of that. If everyone got 2 gig and used 2 gig, then the networks would be slow all the time.
Now that comes down to likely hood of using the data, 2gig in a phone is unlikely, 2 gig in an iPad is more likely, but not all the 2 gig. 2 gig in a laptop, probably. Hence the tethering control apple have in place.
Now FaceTime is a feature that increases the likelihood of using that data allocation, means apple putting in a additional control. By charging for it, the telco dissuades you from using the data allocation.
The problem is when you charge for tethering and FaceTime features and your competitors don't, you immediately stand out.
Wy charge when other don't, I mean data is data surely? Obviously not when your competitors aren't your network is oversubscribed. I think AT&T is just showing how weak and pitiful their third rate network really is.
Even on LTE people are saying how much more coverage the other telcos like Verizon offer over AT&T, FaceTime and tethering shouldn't even be an issue on LTE, unless your network sux.
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