Yeah I think the key words in the bet, were "astrophysical" black hole coming from a star, as opposed to "dynamical" ones coming from mergers. It seems the part

Yeah I think the key words in the bet, were "astrophysical" black hole coming from a star, as opposed to "dynamical" ones coming from mergers. It seems the party doubting dynamical ones thought space was big and they would be unlikely to find each other. As evidence is showing, all kinds of mergers are happening.