I remember that a couple of years ago there was a AIDS incident in the Spanish porn world. I think from that moment they work with closed groups.
I have footage that the PremiumBukkake babe goes through all the test results from all the participating bukkakeros to see that all the men are tested and it save to take their semen. Until that moment there was the possibility as stranger to visit the set and sperm lovely girls like Rebecca Volpetti, Sherry Vine. You can see those advertisements way back in this thread.