"Unlimited: Wherein the amount of bandwidth, measured by megabits/s up/down, will not be artificially affected. While system outages or other technical limitations can at times affect throughput, at no point will AT&T or its subsidiaries place constraints upon throughput based upon the amount of data transferred over the course of one or more billing periods."
If they could, then would they still be able to call the service "unlimited" if they enforced moment-by-moment QoS at the distribution node (so your neighbour's download will slow down to allow you to Skype, as if you were both connected through the same router in a building)?
And if that is allowed, then what is the difference if they're doing the QoSing by long-time-window statistical aggregation rather than packet-by-packet prioritization?
Decreasing the bandwidth available to a given link that has reached some monthly "quota" on a given oversubscribed node†, has exactly the same incentives as decreasing the bandwidth available to a given link for as long as someone else is trying to saturate the pipe with higher-priority traffic.
Either method disincentivizes everyone on the link from "wasting" their bandwidth unnecessarily (in a "you don't want your neighbour to do X, so you stop doing X and hope that they have empathy" way), such that the link becomes less saturated on a long-term basis. But only one is ever highlighted by the news as explicitly breaking the promise of "unlimited." Why is this?
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† (...where that quota is the area-under-the-curve of the router's upstream bandwidth, divided by the number of users attached to the distribution point—in other words, the user's ration of the distribution node's available transit. If the quota is an arbitrary fixed number that isn't anywhere near this number, then that's just price-gouging.)
Both intentionally throttling and not remotely providing the necessary infrastructure necessary to support use will get you into hot waters.
If an ISP usually has enough pipe for everyone on each of their distribution nodes (that is, has no oversubscription—or, more practically, only oversubscription for aggregations of customers with statistically-predictable usage such that the node should reasonably never be saturated, with some extra engineering tolerance for the rare occasions usage goes above statistical norms)—
but the ISP sometimes falls short when the introduction of a new service like VoIP or Netflix or Steam into the market, or lots of new denser construction in an area, makes demand outstrip their supply,
then should they get in trouble for enforcing QoSing (through whatever means) on their distribution nodes, temporarily, while they work on upgrading those nodes?
Because, if so, then ISPs should probably never use the word "unlimited" at all because they would still get in trouble for reasons (almost) completely out of their control.
(I say "almost" because they could just refuse to sell service in oversubscribed areas. But customers would like that even less, if the ISP has a local monopoly. Alternately, ISPs could change to "dynamic billing" where everyone in an oversubscribed area gets billed for non-unlimited service for as long as they're oversubscribed, and then goes back to being billed for unlimited service once the oversubscription is over. This would be cool, but seems like one of those nearly-impossible-with-the-hardware-we've-got sort of things, especially for wireless ISPs where you don't stay on the same distribution node so you're constantly moving between oversubscribed and undersubscribed nodes.)
Even when read in the most beneficial light, no way can the word "unlimited" be interpreted to mean such a thing.
But the FCC Specifically said that companies have the right to employ reasonable network management. 56Kbit/s on the same network others are getting 30Mbit/s is not reasonable by anyone's stretch of the imagination.
"We can handle 20% of users at 5 Mbps, and the other 80% at 250 kBps. So we'll sell the 5 Mbps. But we won't restrict sales to 20% of customers, we'll sell to as many as want it and then throttle to handle overloads on the system." There is no way to make this situation acceptable. Don't sell what you can't provide. Pretty fucking simple.
That definition specifies "artificial" limits, which would - I'd think - exclude technological limitations like oversubscription/saturation.
I doubt rules about advertising are going to change the market, the problem is that tens of millions of people are happy to pay for connectivity without really sweating the details of it.
Essentially, in any given month, you could get throttled/yelled at for going over an arbitrary data cap, which could (and did) vary every month. Given, it was usually above 1 TB, but it was still there.
ISPs got a book thrown at them by the FCC equivalent, saying that if they advertise their product as unlimited, it must be truly unlimited. Literally the next day that decision came out, all ISPs changed their adverts from unlimited to "at will" data caps, which essentially conveys the same marketing message, but isn't a regulated term.
Welcome to the new world, same as the old world, except where we've replaced a word.
I actually complained to the FCC about this very issue. Where my office is, I can see the service degradation progress over the course of the day, peaking around 2PM when everyone's in the office. Should ATT really be allowed to advertise that they provide LTE service here, when every weekday the service provided is much, much slower, if usable at all?
Every service will be limited by local congestion. I'm not sure where this could be going? I get unlimited water from my local water company; but of course the pipes and the number of faucets at my house are practical limits.