Responses are coming in to FCC complaints
Solution. .change to a tiered data plan and pay for what you use.
In my opinion, if they are going to continue to throttle those on unlimited LTE plans, then they should: (1) make it standardized across the nation, and (2) be more clear about where the 5% lies and/or stipulate how close you are when you receive the "warning text."
With respect to (1), you should not be penalized for living in a more remote area where usage patterns might be lighter (i.e. top 5% is a lower GB amount) than in larger cities (where they would probably be higher in general). Conversely, you should not be rewarded simply because you live in a larger area where data usage is likely higher. Granted, this will not come into play until AT&T's LTE is spread across more of the country. But the point is that it should be a nationwide standard as opposed to a "your area" standard.
With regard to (2), the way the response from AT&T reads, they could send you the text telling you you are approaching the top 5%, when you are in the top 5.1% and then throttle you later that day or the next day and technically, they have "notified [you] as [your] usage approache[d] the top 5% of heaviest data users and before [you] experience[d] a change in speed." However, you didn't have much of a chance to alter your usage behavior...
The reason I say this is because it seems that a lot of the posts I've read seem to be saying that they got the notice VERY shortly before they reached the 5%, and that they were throttled within 24 hours.
Maybe they should send you the text when you hit the top 10%, which would actually give you a chance to change your data usage behavior during that billing period before getting into the top 5% and being throttled.
In the future (because of the seemingly inconsistent way that they are handling the throttling), I wouldn't be surprised to see some sort of class action lawsuit alleging that customers who are subject to the same contracts (i.e. we all sign basically the same 2-year agreement, and presumably those that buy their phones outright are still subject to throttling even if they are on a month-to-month contract) are being treated differently under those contracts (i.e. the top 5% being "by area" as opposed to a nationwide standard).
While the contract implies that they can throttle your speeds if you are using too much data, they do not specifically say what their policy is with regard to throttling (e.g. how the 5% is calculated, how long before you reach the top 5% do you receive the warning, etc.), which is generally not a great position to be in if you are the drafter of what is basically a take-it-or-leave it contract.
Even if there wasn't much money from a class action that went to customers, part of the settlement could also be that they have to be clear on their policy, notify all unlimited LTE customers at the beginning of their billing cycle what will constitute 5% for that billing cycle (since it is allegedly based on the prior period's usage), define what the start and end of each period is on which they base the top 5% calculation (since everyone has different billing cycle dates), they have to provide at least "5%" worth of notice (i.e. notify when you reach top 10%) so that you have a decent chance to make efforts to avoid being throttled, and things of that nature. In other words, they may get to keep the ability to throttle unlimited plans, but they have to actually have some consistency to the process for all AT&T customers.
To a certain extent, I'm sure that the above may be a pipe dream.
Regardless, I suspect they will do everything they can not to give in considering the $4 billion hit they are taking for the failed merger and the fact that they want to get rid of as many unlimited plans as possible to make more money with their tiered plans.
Sorry for the rant/ramble...