I shoot a SP-01 with Safety in USPSA Production class. You can chamber a round, however, you have to start with hammer down. The only way to do this is to pull the trigger and using your off hand, hold the hammer and let it down VERY gently. It always scares the crap out of me. If you don't want to do that, you can load a mag, NOT chamber a round, and leave the hammer down. When the buzzer goes off, you'll need to chamber your round. Of course, this "slows" you down.
I just bought a SP-01 Tactical with decocker so I can continue to shoot production class without manually dropping the hammer. The saftey SP-01 is being converted to SAO and I am going to shoot use it for limited class now. With that said, I am going to compete with a different class of firearms and shooters...but I don't really care how I do. I am jsut out having fun.