Rich G.-
I do not wish to hijack this thread but I am compelled to point out that there is no USGA ban on betting, in any amount, provided that the bet is between the players and all money is provided by the players. There is only a prohibition against one who plays for prize money calling himself an amateur. The term "prize money" refers to purses generated by entry fees or sponsorships in organized golf events open for public entry.
Under today's rules a match like the one discussed in this thread, while perhaps not prize money per say, might cause an inquirey because of the involvement of outside money and the public nature of the event. Of course, in this case the question in moot since the participants were professionals.
Calcuttas, pari-mutuals, and other prize pools are a special circumstance and are treated differently.