1. You have to realize that abusive use is relative to the price of the plan. It's like insurance. AT&T knows that in aggregate, even if they offer a $200 35GB plan, so few users are going to buy it that it won't, in aggregate, have any meaningful effect on their network. They know that most data wasters aren't going to buy the $50/5GB plan just to get more data, so the network is safe.
Thus, defining the $30 level at ~3GB or a little less makes sense from an aggregate point of view. They are also counting on the fact that the vast majority of those users are using around 400MB/mo, which is too much for the $20 plan, and not enough for the $30 plan, so they have to buy the $30.
2. If you read it, it applies when AT&T believes it applies.
3. There is a limited amount of network capacity, and it is not fair to allow a bandwidth pig to be slurping 10GB of data and not be paying for it. Why should I experience a slow network on my $25/2GB plan because you're slurping down bandwidth like a pig. If you want to be a pig, use wifi. That's unlicensed, and you can slurp as much as you want through it.
There's no fraud in doing what's in the contract. It is unlimited, and even with throttling, it is still unlimited. AT&T actually has the right to cut off the service, according to the contract, but they are nice, and they throttle instead so that you get slower data speeds, but still have a fully functional iPhone.
This is not a joke. I have to defend reality and what is true because no one else will. Most people are acting like screaming three-year-olds who think they are entitled to whatever they want, and that the contract they signed doesn't apply to them.
You clearly don't understand the issue of aggregate consumption, as well as the many published statistics about average smartphone users and how much data they use, which is around 400MB.
I know what AT&T's motivations are. They want to protect their network, but they have no cajones. They need to grow a pair, and make it a pre-requisite that any upgrade on an account forces the whole account to de-grandfather everything, and once the last line is out of contract, the whole plan is automatically de-grandfathered. At month 25 after a plan is discontinued, the plan should be deleted from the system. This grandfathering is ridiculous.
There are many definitions for abuse. You could easily justify that more than double the median user is abuse. That number is below 1GB. I'd say that's a little draconian. It was simpler when the data plan was 2GB, as that was an easy number that all but the most extreme users fall under.
Deal what is in front of you. What is half of unlimited? If someone offers to sell you something that they know they don't have it is fraud. Their lack of network capacity is not relevent to abuse only their lack of planning. Again you complain about ATT lack of courage while ignoring the fact they are still offering this plan. Your aggregate user is fiction, I believe ATT does not have a contract with him, but even if he did what does that have to do with what ATT sells? Data use is not abuse it is use pure and simple. DUH!
Google grandfathering and why it occured, but it doesn't deal with the issue with throttling. If using a grandfathered plan is abuse then you are abusing the network on your plan which you have stated you do not intend to give up unless ATT forces you. Why are unlimited users held to a different standard. Don't tell me that ATT should do something about it they haven't and won't. Deal with what is front of you. See its so simple even a cave man would get it.