Maybe some people have got guns from them, but it is illegal. Non-clear airsoft guns cannot make their way over the border if they are checked. The occasional package might make its way through without being checked, but don't think that that means yours will. And if (or rather, when) it gets checked, caught, and seized, then you will be blacklisted. Everything shipped to you from then on will be opened at the border, and most likely if you ever try and go across the border, they will search you/your car.
It is NOT worth the gamble. It is illegal. We do not condone nor recommend it in any way. It will be a large waste of your time and money. Just wait until you get AV'd.
I love freedom and consequently America