Not sure I understand your point. Strep A can cause necrotizing fasciitis usually in other parts of the body when it enters the blood stream. However, cases of necrotizing fasciitis in the face and neck are very rare (albeit necrotizing fasciitis is extremely rare already). The only cases reported where due to dental infections and ludwig angina. So, my question is if the bacteria is on our throats (there are silent carriers) and we have lacerations in our mouth where the bacteria could enter the blood stream, why isn’t it more common? The only explanation I found is the saliva and the blood flow in the mouth to quickly cauterize any laceration in the mouth.