Yes, I submitted an unlock request to AT&T. I got a response in 5 minutes. Because it was so quick I assumed it was a rejection.
It turned out to be the unlock code, however, and I promptly unlocked my phone!
I would recommend using your real name and your "good" email address.
Based on other people's experiences I believe that if your name is listed as Joe Anonymous and your email address is junkemail7777@hotmail.com then they're going to assume that you're an opportunist rather than the end user and might not be as likely to fulfill the request.
If you use a GoPhone with a FreedomPop LTE SIM you'll run into one annoying problem. The AT&T Address book constantly tries to assert itself over the FreedomPop messaging app. All you have to do is tap the "back" key, but it's still annoying.
I found a YouTube video that shows how to disable this from happening. It works on the LG Phoenix 2 that a lot of people are using. If it doesn't work on whatever phone you have I'm sure that you can find the dialing code that will let you disable this.
The gist of it is: Dial ##2666## and it will bring up a menu. Tap on "registration" and then choose "complete". That's it. The AT&T address book will finally leave you alone.