Inbreeding to a stallion that has as many good sire sons as Mr. Prospector is inevitably going to occur. In Mr. Prospector's case, the fact that he is a great broodmare sire whose daughters have worked very well with the Northern Dancer and Seattle Slew male lines make inbreeding to him even more likely. His name is becoming so widely spread in top American pedigrees that attempting to avoid him in planning a mating can create a devil's dilemma: do you create the strongest possible match even if Mr. Prospector inbreeding is present and take your chances on the foal's inheriting his flaws, or do you eliminate perhaps the best available stallions from consideration for your mare to avoid doubling up on Mr. P?
Judging by the number of good racehorses of the last few years with two or more crosses of Mr. Prospector (think Orb, California Chrome, She's a Tiger and Mucho Macho Man, to name just a few), more and more breeders are deciding that inbreeding to the great sire isn't such a bad deal after all.