AT&T is apparently cracking the whip when it comes to popular MVNO Net10. The company has announced on its site that new AT&T data caps went into effect on March 1. From here on out, all AT&T SIMs on Net10 will be limited to 1.5GB of high-speed data on the "unlimited" plan. If you want more bytes, a T-Mobile SIM is your only option.
Net10 has always been a bit vague about how much data you can go through before hitting the soft cap. The language used in the blog post appears to indicate this change just moves the cap lower.