I don't know why some of you keep pissing your knickers about this. Firstly, there is no way to track any of the braces that were sold, at least not without a TON of court orders and lengthy investigations that would take up far too much time and resources, with circumstantial evidence at best, especially in this day and age. Secondly, there is no ATF boogieman looking over your shoulder at the shooting range, and I highly doubt the range owner/master is going to phone them up when they see you on the range with a brace. And thirdly, I can almost guarantee you that most street cops in this country don't know a thing about ATF approvals and don't follow them on the regular, and probably also don't know much about pistol braces in general, so the chances that your gun is going to be confiscated by them and you get arrested is slim at best.
If you have them, use them. Just stop with the endless handwringing about it. If they scare you so much, sell them. Hell, send me a PM and I'll buy it from you.....and I don't even own an AR pistol.