There is always the possibility of outliers. If a probability is remote, but not impossible, someone must fall into that bracket. And the probabilities shown in DNA Painter rely on relationships reported by people like you and I, so they are to some extent dynamic and can be subject to change. But confirmation is of course another matter.
I have a match to an individual who I believe to be a 3C at 226 cM. There is a 3% probability of a match at that level in DNA Painter. The individual involved has failed to respond to my enquiries, but after spending more than a year researching his ancestry, I found only one possibility for an intersection of our trees - my GG Uncle, who for want of a better phrase, seems to have "put it about a bit", lived in the same street as my match's GGM. Not only that, but he had a relationship with the GGM's sister at around the same time as my match's GM would have been conceived, resulting in two children out of wedlock, and he later married her.
The father named on the GM's birth certificate seems to be a completely fictitious name, but had the same occupation as my GG Uncle.
Now I can't prove that is the relationship between us beyond a doubt, but it is the only likely possibility I can find. One fly in the ointment is a Great Uncle of mine who seems to have completely disappeared after the 1901 census. He was named as next-of-kin on his brother's army enlistment, but at "address unkown" and is one of my brick walls. However he would only have been 15 when my match's GM was conceived, and GGM would have been 34. Not impossible, but he doesn't appear in any censuses with any of my ancestors in that area after 1901.
My brother's match to the same individual is a more reasonable 131 cM.
I have one other 3C at 113 cM, but all the rest are in double figures bar one - at 9 cM and a proven relationship at a probability of 7% in DNA Painter.
