Cat 1s and Pros are different categories.
I don't know about other promoters, but I promote a low key series of spring races. I do P123 instead of just 2-3 or 1-2-3 because the odd pro will show up, and if I'm not permitted for pros, the pro can't race. I turned away Dave Chauner twice (he of the Philly race with the Manayunk Wall) because I wasn't permitted to allow Pros in the race that year. I've also had to turn away a few domestic pros, including some good friends. I felt terrible doing it. All they wanted was some training, but the liability potential was infinite so I didn't let them race. Ever since then I've done my permits as P123.
It used to be that if you have a Pro license, you couldn't do USCF events, and vice versa. Racers would be banned for taking out pro licenses. When the various federations all came together, pros could do USCF events. Now it's all USAC and one big happy family.
I'm not sure what constitutes a Pro now. I figure they must receive some kind of salary, W2 or 1099 or something. I think it costs more for a Pro license. I didn't bother checking the USAC site, but I think they license all US racers, pros and amateurs.
cdr