I have been a serious multi-platform mobile phone enthusiast since long before there was such a thing as a "Smartphone".
Traveling Internationally for over a decade, I became very interested in all of the many mobile phones of the world. Taking immediate action, I developed a working relationship with one of the worlds largest multi brand distributors in Hong Kong. That was also prior to the establishment of
www.gsmarena.com the first site where people could see all the phones of the world in one place.
Once I had that relationship in place, I was able to buy any phone I wanted, even some they didn't carry, & have it shipped to my office in the US.
I've purchased more phones each year than most other enthusiasts will in a lifetime. Thus my only point is, I have years of first hand experience in the field of mobile phone ownership, having multiple lines & phones. I know almost every trick in the book when it comes to using Unlocked, Unbranded (no carrier), Feature Phones & Smartphones on any GSM based carrier.
Do you really think that AT&T actually has loopholes? A loophole is but a fantasy that the unsuspecting or uneducated user wants to believe exists.
Oh sure, they may talk a good game, and may have gotten away with switching a sim, or swapping a data plan for long enough to brag about their big "cheat" or "loophole".
But I can assure you it didn't last long, nor did they come back to the forum & post about how they got caught & billed retroactively to the start of their scheme.
If anyone thinks they are "getting away" without being noticed, they are hallucinating. Yeah, it might take some time for AT&T to catch it during mass activation periods like iPhone launch madness time each year. But as soon as the smoke clears, the bills will follow. You can count on it.
Don't kid yourself... AT&T, Verizon, and every other carrier are all just like Apple. They are going to milk you for every penny!
If you don't believe it, the only one you're fooling... is the person you see in the mirror.